Sunscreen and Low-fat Diet: A Recipe for Disaster

1. Introduction

Just about everyone in America is convinced of two well-established tenets for how to live a long and healthy life:

-- Eat a low-fat diet,
-- Avoid the damaging rays of the sun

My goal in this essay is to convince you that these two tenets, taken together, are extremely bad medical advice, and that the consequences of our government's success in selling this well-intended but misguided recommendation to the American public are devastating and long-lasting, particularly to our nation's children.

In fact, I have now formed a mental profile of the prototypical mother of an autistic child: she would be a woman who is extremely conscientious about avoiding foods that are high in fat content, she would be very vigilant to protect herself from the harmful rays of the sun whenever she ventures outside, and she would be very careful to stay pencil thin and to keep herself physically fit. In short, to most Americans, she would be the epitomy of good health.

One of the earliest signs of the onset of puberty in girls is the development of shapely curves. Men find such curves to be sexually attractive, an inate instinct that plays into mother nature's goal of assuring a healthy supply of fat for a potential pregnancy. Biological processes intentionally program men to be turned on by curvaceous women in order to assure that women with inadequate body fat (thin and/or muscular women) will be less likely to become impregnated.

The onset of menstruation will not occur until the body fat content rises above 17%. Young female athletes often find that menstruation is delayed, or that their menstrual periods are suddenly shut down, likely because their exercise has upset the ratio of muscle to fat to the point where mother nature considers it a bad bet to risk a pregnancy. Ballet dancers and gymnasts, who must stay thin but still be very strong, are at great risk of having their menstrual cycles shut down completely [1].

Human biology wants fat not just on the person, but also in the diet, if a pregnancy is in the wings. This fact has been proven quite conclusively by a recent analysis of data from the Nurses' Health Study, an ambitious long-term study involving over 18,000 nurses, which has yielded a wealth of data on issues related to womens' health. Dr. Jorge Chavarro at the Harvard School of Public Health analyzed data on their dietary practices over an eight year period, and looked for correlations with various health issues (Dairy Fat Fertility) . Of all the dietary associations that were investigated, the one associating fat in dairy consumption with fertility gave the most striking and statistically significant results. Women who said they ate low-fat diary (e.g., skim milk and low-fat yogurt) increased their risk of infertility by 85%, whereas women who consistently ate high-fat dairy (whole milk and ice cream) decreased their risk by 27% [2].

Consider this: chicken eggs are now considered "unhealthy" due to their high concentration of cholesterol. They are also one of the best food sources of vitamin D. This is to say, a mother hen supplies her unborn chick with nutritional supplements that include a rich supply of cholesterol and a rich supply of vitamin D. Cow's milk is also high in fat, unless it's been manipulated into skim milk, and would be high in natural vitamin D if it weren't pasteurized (the high temperature destroys the vitamin D). We now artificially restore synthetic vitamin D to replace what's been destroyed by pasteurization, a process that can't work well with skim milk, since vitamin D is only soluble in fat, and there is none.

We can conclude that a mother cow loads up the milk she feeds to her newborn calf with fats and vitamin D. Even fish supply their offspring with plenty of vitamin D and cholesterol, as evidenced by the fact that caviar (fish eggs) is high in fat and a good source of vitamin D. Human milk has an even higher fat content than cow's milk; 55% of the calories in breast milk are from fat. It would also be loaded with vitamin D if the mother had not aggressively protected herself from the "damaging" rays of the sun. Mother nature considers it important for newborns, whether chicks or calves or fish or human infants, to be well supplied with fats and vitamin D, in order to assure healthy development.

The most crucial role for both vitamin D and cholesterol in the embryo is in the development of the brain and central nervous system. The human brain makes up only 2% of the body's weight, but it contains nearly 25% of its total cholesterol [3], so it's easy to imagine that the supply chain had better be loaded with cholesterol. One of the critical things that happens during the development of the embryonic brain is the growth of millions of nerve fibers or "axons" to form connections among all the neurons in the developing brain. These axons are coated with a thick fatty substance called the myelin sheath, which provides insulation that keeps the signal intact and allows for fast and long-distance transport with minimal loss. This myelin sheath has very high cholesterol content -- higher than that of any other brain tissue.

According to Ursula Dicke and Gerhard Roth [4], it is the extra length and extra thickness of the myelin sheaths around the nerve fibers of the human brain that most clearly differentiates it from the brains of other mammals. While we do also have more cortical neurons, the difference in their counts between humans and elephants and whales is only about 5%, not enough to account for the observed distinct differences in intelligence. Thus, humans uniquely need even more fat in the baby's milk for a good reason: the infant needs to grow substantially more, longer, and thicker myelin sheaths than any other animal.

2. Cholesterol and Vitamin D: A Brief Introduction

Everybody in America thinks they know what cholesterol is: it's that bad stuff that gums up all your arteries and leads to sudden death by heart attack. If you have too much in your blood, you should be very worried. The argument is then that, to lower the level, you need to adopt a low-fat diet. If that doesn't work, you'll have no choice but to start taking a cholesterol-lowering drug like Lipitor.

There is actually only a weak correlation between high cholesterol and heart disease. Many people with high cholesterol never get heart disease, and, conversely, many people with heart disease have low cholesterol levels. And the ever-so-popular statin drugs lead to many disturbing side effects that should convince the informed reader that they can't possibly be good for you [5] (Statin Side Effects) .

Vitamin D is also familiar as the "sunshine" vitamin: most people remember the story about 19th Century Great Britain and the rickets epidemic, brilliantly solved by the realization that rickets is a consequence of vitamin D deficiency, a problem which can easily be solved by getting out in the sun. Recently, researchers are finding out more and more critical roles that vitamin D plays, far beyond strengthening the bones, in diverse systems throughout the body. One thing most people may not realize is that vitamin D and cholesterol are chemically almost indistinguishable. Vitamin D is manufactured in the body from cholesterol , specifically, from 7-dehydrocholesterol, through a very small change in chemical structure (which involves dropping a single hydrogen molecule) [6] (Vitamin D from Cholesterol) . This happens in the skin, and only happens if a catalyst in the form of ultraviolet rays from the sun, is present. If you're wearing a sunscreen with an SPF level of 8 or greater, then you're pretty much guaranteeing that you won't generate any vitamin D.

Furthermore, cholesterol is the predecessor to a host of other factors that the body uses as catalysts for all kinds of biological processes. For example, testosterone, the male hormone. And cortisol, a hormone produced by the adrenal glands that plays a critical role in managing stress. Furthermore, the myth that high cholesterol is bad is not borne out by the facts. In 1990, researchers from 19 studies worldwide met in Bethesda, Md, to compare results on cholesterol studies, and produced plots summarizing their conclusions ([7], p. 81). For women, there is, over the entire curve, an inverse correlation between cholesterol levels and mortality rates. That's right: the lower the cholesterol reading, the more likely she is to die. It is true that men with very high cholesterol (> 240 mg/dl) have an increase in mortality due to an increased incidence of heart disease; however, mortality increases on the low side as well (below 160 mg/dl), due to increased risk of cancer and respiratory and digestive diseases. This means that both men and women have higher mortality if their cholesterol levels are too low. Women should worry only about low cholesterol, never about high cholesterol.

But my concern is not so much about the longevity of the adult, but rather the health of the unborn child; specifically, the unborn child whose mother conscientiously adheres to the regimens of a lowfat diet and sun avoidance. If her cholesterol levels are high, she will likely lament that fact. But one thing she won't do, if she's planning on having a child, is take a statin drug like Lipitor to lower her cholesterol readings. The reason is simple, although not widely advertised by the drug industry. Statin drugs will with high probability render her unborn child non-viable. Researchers at the U.S. National Institutes of Health found severe abnormalities in the central nervous system, as well as limb deformities, in nearly 40% of the babies in a study of women who took statins during the first trimester of pregnancy [8] (Statins in Pregnancy) .

Statins are labeled as a category X drug with respect to pregnancy by the Food and Drug Administration, the same category as that given to Thalidomide. If you are above a certain age, you will remember this infamous drug that swept Europe by storm in the 1950's. Widespread use of Thalidomide led to an epidemic of infants being born without arms; without legs; without ears; deaf. They eventually traced the source to the new wonder drug that was supposed to be a calming tranquilizer with essentially no side effects. A pregnant woman who takes Thalidomide between the 4th and 7th week of her pregnancy has a 20% or greater risk of producing a baby that is missing significant body parts. But at least these children were mentally sound. Their brains were generally fine, and they grew up to have normal intelligence, which allowed them to lead productive lives. The effects of statin drugs are so potent that there's little hope for survival, let alone anything resembling a normal life. This outcome is due to the disruption of a critical step in a biological pathway that leads to the production of cholesterol, an essential building block of the nervous system.

A serious disorder known as ("Smith-Lemli-Opitz") " syndrome (SLOS) is characterized by a genetic defect resulting in an inability to synthesize adequate cholesterol. Most fetuses that are unfortunate to be conceived with this genetic defect don't make it to 16 weeks of gestation before the pregnancy ends in a miscarriage. If they do manage to make it to term, they typically suffer from major brain defects, resulting in autism or other forms of mental retardation [9].

Thus far, I've spoken about the roles of cholesterol/vitamin D in preventing rickets and in brain development. I will return to the topic of brain development in a moment, but first I'd like to list only some of the conditions/syndromes/illnesses that are, in my view, associated with vitamin D deficiency in children. I will argue that many conditions frustratingly growing in prevalence in today's youth in America can be explained by a simple theory that combines vitamin D deficiency with fat deprivation. Some are a consequence of the poor regimen of the mother while the child was in the womb and/or nursed. Others are principally due to the continued deprivation that the child experiences after it's born. Surely many are influenced by both the mother's and the child's deficiencies. The list includes childhood obesity, teenage adult-onset diabetes, increased incidence of broken bones, increased frequency of everyday illnesses such as colds and flu, autoimmune disease, teenage depression, asthma, allergies, and Attention Deficit Hyperactivity Disorder (ADHD).

3. The Rise of Autism in America

While all the items I listed above are not trivial problems, they pale by comparison to the impact of the rise in rates of autism. I will cover these other conditions in a separate essay, and explain more fully my reasons for believing that they are caused by the cholesterol/vitamin D deficiency syndrome. But here I want to focus on autism. While I believe that genetic predisposition plays an important role, I also think that many of the new cases could have been avoided with only minor changes in lifestyle.

In America, the rates of autism spectrum disorders (which include autism and the milder form, Asperger's syndrome) have increased alarmingly over the last thirty years: in the 1980's, there were at most 4-5 cases reported per 10,000 population. Today it's estimated to be 66 per 10,000, a relative increase of 1200% or more [10] (Autism Statistics) . Many autistic children will never be able to function independently as an adult. In the most severe cases, the IQ tests below that of a Down's syndrome child. They live in self-imposed isolation, and it is extremely challenging to try to teach them basic skills of life. Asperger's is a much milder form of the disease. Asperger's children often test to have IQ's that are above average, but they lack intuitive social skills and come off as odd and awkward in social settings.

Dr. John Cannell, who is a psychiatrist and prominent advocate for vitamin D, believes that our nation's aggressive efforts to protect ourselves from the sun through excessive sunscreen and sun avoidance may be behind the epidemic rise in the incidence of autism. He has founded a non-profit advocacy group called the Vitamin D Council , and has published extensively on the Web to educate our population about the many benefits of vitamin D. He seeemingly fights a losing battle, however, against the powerful lobbying powers of the well-oiled sunscreen industry, who are raking in the dough due to a 30-fold increase in sales of sunscreen products since the 1980's.

Dr. Cannell points out that the skyrocketing rise in autism rates coincides with the introduction of widespread practices to avoid unprotected exposure to sunlight, a message that has been pounded into the American public since the late 1980's. I would add, however, that coincidentally, the appearance of a multitude of products advertising the virtues of their low-fat content was, in my view, an equal contributor to the problem. The deadly combination of a simultaneous switch to low-fat diet and sun avoidance is the real culprit.

4. The Roles of Cholesterol and Vitamin D in the Brain

As I've already mentioned, the human brain is characterized by an overabundance of well-conditioned nerve fibers. All of these fibers are coated with a fatty myelin sheath that is critical to their ability to carry a signal from one neuron to another one, especially one that is some distance away. The human infant must construct this marvel of nature from raw materials it obtains from the mother's supply chain.

Not only is cholesterol a core building block of the brain, but also vitamin D plays a critical although not well-understood role in brain development. Researchers at the University of Queensland in Australia have studied brain development in embryonic rat brains in order to assess whether low maternal vitamin D might affect brain development [11]. First of all, the vitamin D receptor (VDR) is prevalent in brain cells, a clear indicator that vitamin D plays some role (Vitamin D in Nervous System) . These researchers determined that the VDR appeared simultaneously with the well-described stage when there is an increase in apoptotic cells and decrease in mitotic cells during brain development. Apoptosis is a natural process that programs the cell to die; mitosis is the process of splitting to become two cells instead of one. Thus, these processes are controlling which cells live on to become integral parts of the final brain and which cells are judged to be useless and therefore pruned.

In addition to the nerve fibers, a substantial component of the brain is made up of so-called glial cells, which intermix with the neurons and are thought to provide nutrients and to regulate apoptotis and mitosis, i.e., which nerves live or die during pruning stages. In 1997, it was discovered that a factor secreted by glial cells played a critical role in facilitating the growth of synapses, which are the locales of junctions between nerve fibers. By 2001, this unknown factor had been identified as cholesterol. A decisive study showed that externally supplied cholesterol could substitute for this glial substance to produce highly efficient functioning synapses. Furthermore, if cholesterol was removed from the glial secretion, it lost its ability to stimulate synapse growth.

Another critical role that cholesterol plays in the nervous system is in forming areas in the cell membrane where certain proteins important to cell signaling are anchored. In a 2004 study, it was found that these so-called lipid rafts stimulate and guide the growth of nerve axons. Cholesterol deprivation has been demonstrated to destroy the axon's ability to grow in the proper direction.

Professor Bartzokis, professor of neurology at UCLA's David Geffen School of Medicine, has been conducting very fascinating research over the past several years on the role of myelin sheath in neurological disorders [12] (UCLA Study) . While Alzheimers is perhaps his main area of interest, increasingly of late he has come to believe that defective development of the myelin sheath in the nerve fibers of the developing fetus's and/or infant's brain could be one of the critical factors that leads to autism. He also suspects that ADHD could be caused by a disruption of brain growth during early childhood. He hypothesizes that ADHD and autistic spectrum disorder could be due to the same toxic chemical, but that the exposure occurred at different points in the child's development. I.e, that different parts of the brain are myelinated at different times, and, depending on when the damage was done, the symptoms could manifest as either autism or ADHD. While he seems to suspect a toxin in the environment, I believe that it could be attributable to an absence rather than a presence: the absence of an adequate supply of both vitamin D and cholesterol.

In an interview, Professor Bartzokis was quoted as saying "The thicker and heavier the cells' coat, the faster and more effective their communication. Myelination, a process uniquely elaborated in humans, arguably is the most important and most vulnerable process of brain development as we mature and age."

As I said before, the myelin sheath, which insulates all the nerve fibers in the nervous system, is made entirely from fat. In a series of experiments, researchers in Bartzokis' lab have demonstrated, very logically, that a thinning and breakdown in the myelin sheath can expose the nerve beneath, with the likely consequence of a multitude of neurological and behavioral problems. Without adequate insulation, cells won't be able to communicate intact signals to one another.

A recent study which measured cholesterol levels for children with autism found a striking correlation between low cholesterol and symptoms of either autism or Asperger's syndrome (Cholesterol Deficiency and Autism) . Autism has also been shown to correlate with a brain developmental defect that is manifested as an over-emphasis on local as opposed to distant communications in the brain. It makes sense that long nerve fibers would be more vulnerable to defective growth simply because they are long, so it could be a smart strategy to focus on the short connections, given insufficient resources. Thus, the most affected nerve fibers would likely be the long distance communication networks linking up with neurons present in the external sensory system: the eyes and the ears, for example. Sound signals (e.g., speech) picked up by vibrations at the ear drum are encoded by the cochlea in the inner ear and then transported to multiple way stations in the brainstem, the thalamus, and finally the primary auditory cortex in the temporal lobes at the sides of the head. Backwards pathways relay feedback from the auditory cortex all the way back to the inner ear, to provide excitatory and inhibitory influences, contextualizing the interpretation of the incoming signal. All of these pathways require a high quality myelin sheath to assure signal integrity along the way. Similar long distance and multiple station pathways exist for the visual system.

Defective myelin would affect a child with autism all along these pathways, leading to an inability to process the speech he is hearing or the visual scene in his field of view. This garbling of the signal's message would naturally result in a tendency to want to shut out all external stimuli, due to the noise and confusion they provide.

5. Brain Development in the Young Child

A human child's brain undergoes tremendous development outside the womb: mostly from birth to two years of age. As the child experiences sensory inputs from the eyes, the ears, the skin, it sprouts a massive overgrowth of nerve fibers and connects these up at millions of synaptic junctions throughout the brain. For this growth to take place, it needs, as I've just said, an abundant and steady supply of both cholesterol and vitamin D, which it should be getting from its mother's milk supply, as well as its own exposure to the sun.

On a good supply of fatty mother's milk, the human baby quickly fills out with layers of fat on its thighs and upper arms. It's almost instinctive to react to a fat baby as a healthy baby. I believe one of the biggest roles all this extra fat plays is to maintain a reserve supply of nutrients to help feed the rapidly growing brain. By the age of two the child has typically thinned out, but in the mean time this body fat has served as an excellent buffer to maintain a consistent supply of fat to nourish the explosive growth of myelin sheath throughout its brain.

As you will see in the next section, calcium acts as a catalyst to increase the efficiency of fat metabolism, and vitamin D is critical to calcium absorption from the gut. So a child with insufficient vitamin D would need substantially more fat cells to accomplish an equivalent delivery rate to the brain. Furthermore, the process of nerve growth and synaptic attachment both depend on vitamin D and cholesterol to perform correctly, as was described in the last section.

At around the age of two, the normal child's brain undergoes a massive pruning stage. Through the sensory experiences it has accumulated during its first two years of life, the glial cells in its brain have been constantly making note of which fibers transmitted useful signals to which neurons at which synapses. It has been adjusting synaptic weights correspondingly, and it is now prepared to identify those nerve fibers that turned out to be counterproductive. A process of apoptosis (cell death) ensues on a magnificent scale.

In studies on the brains of autistic children, it has been observed that one of the most striking anomalies is that their brains seem to be unwilling to perform the massive pruning through apoptosis at age two [13]. This could be because their brain's glial cells don't know which nerve fibers are unproductive. Signal transmission was unreliable throughout their first two years of life due to the poorly constructed myelin sheath. As the signal tried to travel down a pathway, noise eventually overtook it, and the distinction between productive and unproductive pathways was hopelessly blurred. To compound this problem, as we have seen, the signaling to control apoptosois depends critically on both cholesterol and vitamin D, so that, even if a glial cell was aware that it should prune a particular axon, it might not be able to execute on that plan.

6. What about Calcium?

Milk provides at least three critical nutrients to the newborn: fat, vitamin D, and calcium. Obviously, calcium is needed in rich supply for the developing bones and teeth. But calcium also plays an important role in many biochemical processes throughout the body, particularly in the immune system and the developing nervous system [14] (Calcium Role in Neonatal Brain) . In the brain, communication among distant nerve cells depends on the active transport of calcium across cell membranes. Defects in calcium transport have been associated with autism spectrum disorder in several rare genetic diseases. This is one of the few areas where the search for specific genetic factors for autism has born fruit [15] (Calcium Autism Genetics) . For example, Timothy syndrome, known to be associated with calcium transport defects, causes a multitude of problems, including immune system disorders, congential heart disease, seizures, irregular sleep patterns, small and decaying teeth, etc. It is suspected that as many as 80% of people with Timothy syndrome have autistic spectrum disorder.

Skim milk is obviously missing the fat. The vitamin D artificially added to skim milk will be poorly absorbed due to the lack of associated fat. But what about the calcium? The good news is that calcium is water soluble, so when the fat is removed, all the calcium stays behind in the milk. The bad news is that, as for vitamin D, the lack of fat interferes with the absorption of the calcium through the gut. If you pour the milk over a bowl of bran flakes, you further reduce your ability to make use of the calcium. In a study involving 142 women [16] (Calcium Absorption in Women) , researchers found that those who had the highest ratio of fat to fiber in their diet were best able to utilize dietary calcium, while those who ate the least fat and the most fiber wasted a good part of their calcium intake. Of course, vitamin D deficiency itself, easily a consequence of sun avoidance, has a severe impact on calcium absorption. Promoting the absorption of calcium in the gut is the best-known biological function of vitamin D.

7. Gestational Diabetes

I am now going to take a moment to discuss more generally the topic of nutrition and food science. Once I have laid down the groundwork for basic nutrition, I will return to the subject of the pregnant mother, jeopardized by her inadequate diet and lack of sun exposure, whose body, when faced with nearly insurmountable obstacles, desperately attempts to maintain a steady supply of fat to the developing fetus' brain. I will try to make the arguments as simple as possible, although the biological mechanisms at play are not simple.

First, I would like to recommend a great book, Good Calories Bad Calories by Gary Taubes [7], for those who want to seriously examine the issues of diet and health. Most of what is written in this section was gleaned from reading that book, although I have added a few embellishments, based on my own reasoning. The main message of the book is that our country has been grossly misled into believing that a low fat diet is a healthy diet. This message is now so thoroughly entrenched that it is nearly impossible to overturn. While his main focus was on diets that would be effective for weight loss, he also argued persuasively that a high fat diet (or at least a low-carb, high-quality fat diet) is a healthy sustainable nutritional practice even when you're not trying to lose weight. He advocates a diet that eliminates as much as possible refined sugars (white sugar) and refined carbohydrates such as white bread, white rice, and pasta.

The biggest problem with these foods is that they are digested too easily. This causes a spike in the blood sugar level which in turn causes the pancreas to get into high gear,overproducing more than enough insulin to break down these sugars, so that they can be stored by the liver as glycogen for future energy needs. One consequence is that the insulin receptors become increasingly less responsive to insulin, leading over time to type II diabetes: an inability to efficiently utilize insulin. Diabetes is easily diagnosed by measuring the levels of sugar in the urine, because the excess sugar that was not broken down due to insufficient insulin eventually is excreted by the kidneys as waste material.

Insulin plays a critical role not just in the processing of carbohydrates, but also in the processing of fats. Interestingly, high levels of insulin in the blood promote the storage of fat in fat cells. Conversely, low levels promote the release of fat from fat cells into the blood stream. This makes good sense, because, when there is plenty of sugar in the blood, the cells can use that sugar for their energy needs, or it can be converted to fat and stored in the fat cells for later use. During fasting conditions, insulin levels drop, and the fat cells are encouraged to release their fat stores to supply the energy needs of the muscles and brain [7, p. 432].

A typical person goes through a wake/sleep cycle every day. Insulin levels fluctuate throughout the day depending on the times and contents of the meals. However, at night, while a person sleeps, the insulin level drops, and low insulin acts as a catalyst to allow the stored fats to take their turn in supplying the body's nutritional needs during the long fast. Calcium plays an important role in fat metabolism, and vitamin D therefore plays an indirect role by promoting the absorption of calcium into the blood stream from the digestive system. A person with inadequate vitamin D (or with inadequate calcium in their diet) would need to carry a larger reserve of body fat to maintain an equivalent rate of fat delivery during fasting [17] (Fat Metabolism) .

The reason why I have taken the time to describe these nutritional regulatory mechanisms is that I think they can be used to explain a well-known phenomenon called gestational diabetes, while at the same time lending support to the idea that the pregnant mother's body may become preoccupied with supplying adequate fat to the growing fetus. Gestational diabetes is a poorly understood phenomenon where a woman who had shown no signs of diabetes in the past suddenly starts passing sugar in the urine while she is pregnant. It seems to me that a possible explanation can be found if we make the simple assumption that the mother's body is trying desperately to maintain an adequate supply of fat for the embryo. If she is practicing a low-fat diet regimen, then it will be imperative to extract fat from the fat cells in her body and release it into her blood stream, whence it will eventually reach the placenta and make its way into the baby's blood stream, and, ultimately, delivery to the baby's developing nervous system. However, as we've just seen, in order to get the fat cells to release their fat, the insulin levels will need to be low. A vitamin D deficiency will compound the problem: with inhibition of calcium uptake, even lower insulin levels will be needed to achieve a comparable effect.

Because of inadequate insulin in the blood, sugars entering the blood stream from the digestive system cannot be fully broken down. The consequence would be waste sugar showing up in the urine, manifesting itself as gesticular diabetes. However, not all of the excess sugar would be wasted: some of it would make its way into the fetus's blood supply, which would then trigger its fledgling novice pancreas to produce its own private supply of insulin. The baby would then be able to convert the excess sugar into its own personal supply of body fat, which will turn out to be extremely useful to it once it is born.

Any baby who is unusually large at birth is often a sure sign of gestational diabetes. But also, in my view, this excess fat at birth is a clear clue as to why gestational diabetes is useful to the fetus: gestational diabetes is invoked as a mechanism to help the fetus survive in the face of a severe shortage of fat supply from the mother. The child is likely to face a continued shortage of fat supply from the mother's milk after it's born. The same mother who had an insufficient amount of fat in her diet during pregnancy will likely continue to do so after the birth.

In summary, it seems to me that the reason that gestational diabetes occurs is that the mother's body is willing to waste some of the sugar that's ingested during pregnancy so that the mother's fat cells can release their stores of fats into the blood stream to supply the baby's immediate needs of fats for its developing brain. At the same time, the fetus can utilize the excess sugar to protect itself from future fat deprivation. If the mother, in addition to eating inadequate fats, is also deficient in vitamin D, it will be that much harder to get at the nutritional lodes of the fat cells, leaving her child in grave jeopardy. If, finally she has very few fat cells to begin with, then there just may not be another alternative besides severely compromising the child's developing nervous system.

8. Demographics of Autism and Vitamin D Deficiency

The Vitamin D Council has compiled an 11-page document detailing a persuasive theory that vitamin D deficiency causes autism [18] (Vitamin D Deficiency and Autism) . In this section, I will just highlight a few of the points discussed there.

There are interesting demographics with autism, both in terms of gender and race, that can be explained by differences in vitamin D responses. Boys are four times as likely as girls to be diagnosed with autism. This could be due to the striking differences in the effects of estrogen vs testosterone on vitamin D metabolism. Estrogen appears to have "multiple enhancing effects" on vitamin D metabolism, whereas researchers have been unable to demonstrate any relationship between testosterone and vitamin D.

An astounding 96% of black pregnant women have been found to have vitamin D deficiency. This is likely due to the fact that their dark skin contains so much melanin that they are unable to efficiently generate vitamin D from sun exposure. Blacks in America have also been found to suffer from a substantially higher incidence of autism.

Autism rates in Europe are strikingly higher among dark-skinned immigrants. The incidence of autism in Sweden for children whose mothers immigrated from Uganda was 15% -- 200 times higher than the rate in the general population. Immigrants from Somalia to both Sweden and, in the United States, Minnesota, also show extraordinarily high rates of autism [19] (Somali Autism) . 25% of the children in Minneapolis' early childhood autism program are from Somalia. I think this is a very interesting statistic, because, in both Minnesota and Sweden, fish is an important part of the diet, yet the traditional Somali diet does not include seafood [20] (Somali Diet) . Fish is an excellent source of both vitamin D and omega 3 fats. The Somali children are likely doubly disadvantaged both due to their dark skin, living in a northern climate, and their inadequate consumption of fish.

Another way to infer a link between autism and vitamin D is to study associations of autism rates with weather patterns. A recent study conducted by Michael Waldman at Cornell University investigated the relationship between the amount of rainfall and autism in the West Coast states of the United States [21] (Rainfall and Autism) . It was found that autism rates correlated remarkably well with precipitation rates. The counties that had the highest rainfall showed a 30% higher rate of autism than counties with the least rain. The most straightforward explanation for this result is the truism that children in rainy environments experience less sun exposure, and hence are more likely to be vitamin D deficient.

9. Autism and Infertility

As of 2001, 1% of the children born in the U.S. were conceived through IVF. This population group forms an interesting set to study, because, logically, if infertility is a common consequence of excessive diligence in maintaining a thin, muscular body and a low-fat diet, then we would expect the infertile population to include a significantly larger percentage of such mothers than the fertile population. Furthermore, if these practices lead to an increase in autism, then there should be a larger than normal number of autistic children among the offspring of IVF pregnancies.

There have not been sufficient research funds devoted to the question of studying the health of children born from IVF. Nonetheless, one compelling study was recently conducted by Mary Croughan of the University of California, San Diego, funded by the federal government [22] (IVF-Autism) . In this study, which was presented at the American Society for Reproductive Medicine (ASRM) conference, she compared children resulting from IVF with children conceived naturally. She examined more than 19,000 medical records, and the only cases of autism and Attention Deficit Hyperactivity Disorder showed up in the IVF children. She also found an increased risk of certain birth defects, cognitive delays, and behavioral problems among the IVF children. These results could be due to some damaging aspect of the IVF process itself, but it's also plausible that the source of the infertility and the source of the autism are the same thing: inadequate fats and vitamin D.

10. Autism and Twins

One excellent way to tease apart the nature v.s. nurture debate on any syndrome is to study twins. Several studies have been conducted on autism demographics, and these have uncovered some intriguing statistics concerning twins. One very informative study investigated families where exactly two of the children had autism [23] (Autism in Twins) . The investigators determined, as might be expected, that the identical twin of an autistic person was twelve times as likely to have autism as a mere sibling of an autistic person. However, if autism were solely due to genetics, then the concordance for identical twins should be 100%. Instead, one third of children whose identical twin has autism do not. More intriguing however is the result they obtained for fraternal twins. If your fraternal twin has autism, you have four times the chance of also having it, compared to someone whose sibling, born at a different time, has it. Since fraternal twins are no more closely related genetically than siblings, this has to be interpreted to mean that being a twin is a risk factor for autism.

This statistic narrows down the possibilities enormously, and strongly suggests a role for the shared environment of the twins. Two things immediately come to mind: (1) they share the mother's womb during the fetal stage, and (2) they compete for the mother's milk in infancy. A mother who is deficient in fat, vitamin D, and calcium will face an even more insurmountable problem when tasked with carrying to term and then nursing two infants than would be the case for a singleton birth. A scarce resource is made twice as scarce by the simple fact that there is now double the demand. And thus twins would easily be expected to be more susceptible to autism than singletons.


11. Sunscreen Isn't Working

Since the 1970's, our country has witnessed a 30-fold increase in the sales of sunscreen products, alongside a 30% increase in deaths from melanoma[24]. You might think that this is just due to cases in the elderly that were caused by bad practices many years ago. However, the incidence of melanoma has been consistently rising in children by about 3% per year since the 1970's [25] (Melanoma in Children) . Isn't it time to admit that sunscreen is not useful? Even the sunscreen executives will admit that they have never been able to find evidence that sunscreen prevents melanoma. However, it's unfortunately easy to sell the simplistic idea that, because the sun's UV rays can cause cancer, and because sunscreen blocks these rays, then sunscreen must, quite logically, prevent cancer.

The reason this formula is incorrect is very simple: sunscreen also blocks a mechanism that biology put in place many millions of years ago, also for the purpose of protecting us from the sun's rays. Biology's own mechanism, however, is far more effective than sunscreen, because it produces products that linger on our skin (melanin) and in our blood stream (vitamin D) long after the particular outing to the beach has passed. In the spring, if we go outside without sunscreen, we will slowly pick up a protective tan, while also generating a good supply of vitamin D. By the time the summer comes around, the tan affords protection from the sun's harsher rays, and we continue to accumulate vitamin D, which will be able to carry us through the lean winter months, when sunlight is in short supply.

Melanin in the tanned skin prevents the sunburn in the summer. Vitamin D in the blood stream protects us not just from skin cancer, but from just about any cancer you can name. If you type "vitamin D" into a search engine along with "prostate cancer," "breast cancer," "ovarian cancer," "pancreatic cancer," etc., you will find that the entire first page of the result is filled with pointers to studies that show vitamin D affords significant protection from that cancer. For instance, a controlled study conducted at the Creighton University in Nevada showed that people who were given supplements of Vitamin D and calcium experienced a 77% reduction in cancer incidence over those given a placebo [26] (Vitamin D Prevents Cancer) .

You might think that you could get the best of both worlds by liberally applying sunscreen and taking lots of Vitamin D orally. But this is a tricky game to play. Sunscreen may give you false security by preventing the sunburn that provides a warning signal to get out of the sun [27] (Issues with Sunscreen) . And oral vitamin D may not be properly absorbed if it's not accompanied by ingested fats to dissolve the vitamin D. If you just take excessive amounts to compensate for this problem, you can run into toxic reactions and a suppression of the immune system, the opposite of the effect of sunlight [28] (Issues with Vitamin D Supplements) . Better to trust biological mechanisms which have had millions of years to perfect the natural process that exploits the sun's rays to beneficial effect. In my view, a large part of the reason that we are losing the war against cancer is that we are increasing the base rate significantly through the excessive use of sunscreen products.

12. Low Fat Diet Isn't Working

The American Medical Association started aggressively campaigning in the 1970's that a healthy diet is one that is consistently low in fats. and they have maintained that message as the "party line" ever since. Today, you can't go to the grocery store without seeing row upon row of foods advertising themselves to be "low fat", "nonfat" or "fat free," constantly bombarding you with the subliminal message that fats are bad for you. Meanwhile, forty years later, America is facing an epidemic of obesity that is contributing to a host of health problems, not only for aging adults but also for young children.

Is there, then, a relationship between low-fat diet and obesity? Gary Taubes, for one, thinks so. In his book, Good Calories Bad Calories, he presented an overwhelming amount of evidence to show that the easiest and most effective way to lose weight is to adopt a high-fat, low-carb diet. A high-protein diet can not be sustained, because after a while the dieter just can't face another lean pork chop. With a high-carb diet, the dieter is constantly suffering from hunger pangs, while losing little if any weight. But a high-fat diet, such as the Atkins diet, works relatively painlessly, in part because fats take longer to digest, and leave you feeling more satiated.

It might seem logical, since fatty tissue is made of fat, that a low-fat diet might help prevent you from becoming fat. Ironically, exactly the opposite is true. Humans are fully capable of manufacturing fats from carbs -- a process that takes place in the liver with the help of insulin. These manufactured fats are then dispatched to distributed locations throughout the body, where they can be stored away in fat cells for later use. My belief is that, once biological monitoring mechanisms recognize that there is a distinct shortage of fats in the diet, the appetite is automatically adjusted upwards, to compel the person to consume more calories in a given day than they can burn off. This has the intentional effect of accumulating a store of reserve fats on the body, a metaphorical silo, which can then provide a steady stream of fat nutrients to the muscles and brain to overcome the glaring deficiency in the diet.

If, in addition to consuming a low fat diet, the person also aggressively avoids the sun, then the problem will be compounded, and they will likely gain even more weight. This is because of the role calcium plays in the efficiency of fat metabolism, and the role vitamin D plays in the absorption of calcium.

It has now become evident that not all fats are created equal. The culprit that's responsible for the "fats are bad" message is partially hydrogenated oil, or "trans fats." These synthetic fats are created by loading up liquid vegetable oil with hydrogen and then heating it, along with a metal catalyst, to a high temperature. The result is a fat that stays solid at room temperature and survives a long time on the shelf. Once companies figured out how to do this well, all kinds of processed foods, most notably margarine, but also crackers and cookies, started appearing on the grocery shelves. These products don't get rancid at room temperature because even the microorganisms that would spoil them are smart enough not to consume them. If you consume them in large quantities, your "LDL" (bad) cholesterol levels will go up, and your "HDL" (good) cholesterol levels will go down [29] (Wikipedia) . A survey issued by the Food and Drug Administration in 1999 [30] (Trans Fats Survey) determined that these fats constituted 95% of the cookies, and 100% of the crackers found on supermarket shelves. Companies are now scrambling to find ways to replace the trans fats in all their products.

The media recently has begun to sing the praises of "Omega 3" fats, found in large amounts in fatty fish such as sardines and salmon. Researchers have discovered that eskimos, whose diet is extraordinarily high in fat, have excellent health with respect to heart disease prognosis. A recent study by Fombonne et al. found that the Inuit of northern Quebec appear to be completely free of autism [31]. Not a single case was found among their children. This fits well with the theory presented here, since they eat an extremely high fat diet, consisting of large amounts of seal blubber and fatty fish like salmon. These are both excellent sources of both fats and vitamin D.

Unfortunately, pregnant women have in recent years been discouraged from eating fish, due to the high contamination with mercury, which is believed to cause damage to the developing fetus. It is frustrating that mercury contamination (a valid concern) stands in the way of getting adequate omega 3 fats for the baby. However, recent studies have pretty much dispelled the theory that mercury might cause autism. Several studies have now confirmed no link between mercury and autism. In fact, in California, after mercury was eliminated from the vaccines, the incidence of autism continued to rise [32] (Mercury and Autism) .

Although fish is the best source, a surprising number of pallatable foods also contain Omega 3 fats, including walnuts, strawberries, tofu, cauliflower, spinach, and scallops [33] (Food Sources of Omega 3 Fats) .

As has been convincingly shown by the Nurses' Study, if you want to become pregnant, you will significantly improve your chances by enjoying plenty of whole milk, butter, and ice cream. You will also, in my view, significantly improve the chances of producing a healthy child by continuing to maintain a high fat diet throughout the pregnancy, and while you are nursing the baby. It is important, however, to choose foods carefully so as to assure a good steady supply of omega 3 fats, and to religiously avoid consuming trans fats. There is no place for a low fat diet during pregnancy and lactation.

13. What Can be Done To Fix the Problem?

If you have read this far, I hope you are convinced that there may be validity to the main thesis of this essay: that low-fat diet, combined with inadequate vitamin D, both in the mother and the child, are major contributors to the autism epidemic in America. I have been researching this topic off and on over the last 20 years, exploring plausible explanations for the alarming rise in the incidence of autism in America. To me the evidence I've found is pretty compelling, and I felt it would be unethical to stand by and watch more and more cases of autism appear without at least attempting to articulate this theory to the best of my ability, to put it "out there," with the hope that others may also be persuaded and spread the word.

However, I will concede that thus far there is no definitive study that would leave no doubt that this hypothesis is correct. This, more than anything else, is what's needed to really convince people to dramatically change their practices, to unlearn all the misguided advice they've been given previously about the benefits of sunscreen and low fat diet.

This country is capable of responding quickly once a convincing study dramatically changes expert opinion. Witness the case of Hormone Replacement Therapy (HRT), widely recommended to menopausal women to help them cope with hot flashes and, it was claimed, to improve their odds against cancer. A large randomized clinical trial of estrogen and progestin, based on the Women's Health Initiative, was aborted prematurely because the results so clearly favored the women who did not take the drugs. The study showed clear evidence that the drug contributed to increased risk of developing both breast cancer and heart disease [34] (Breast Cancer and HRT) . The response was immediate and dramatic: prescriptions were left unfilled, the stocks of drug companies plummeted, and within a short time survival rates for breast cancer started improving.

I'm confident that a similar study could be done on autism and its link to vitamin D deficiency and low-fat diet. It could be that a meta analysis of the Nurses' Health Study is all that would be needed. It might require further interviews to determine whether the mothers of autistic children tend to practice low-fat diet and over-zealous sun protection. Blood tests could be performed to measure the levels of vitamin D among autistic children and their mothers. Individual children could be put on a program to make sure they get enough vitamin D and fat (especially omega 3 fats) in their diets. These children could be subsequently monitored to see if their autistic symptoms show any improvements -- although it might be too late to correct the damage already done to their brains. If such studies were to obtain convincing results, the American people would respond quickly and effectively, as they have before in the case of hormone replacement therapy.

Lately, and with increasing frequency, the media have been drawing our attention to the alarming discovery of an epidemic of vitamin D deficiency among our nation's children. [35] (Vitamin D Deficiency Epidemic) . My belief is that this is directly attributable to the well-intentioned but over-aggressive application of sunscreen. At the same time, experts are beginning to sort out the complex situation with the many kinds of good fats and bad fats that exist naturally and through artificial chemical manipulations -- they have come to appreciate that the issue is not so much low fat but high quality fat in the diet. The public is slowly becoming educated about these new revelations, and, hopefully, major lifestyle modifications will soon ensue, with positive outcomes.

References

1. Frisch, R.E., Wyshak, G. and Vincent, L., "Delayed Menarche and Amenorrhea in Ballet Dancers," New England Journal of Medicine, Vol. 303, No. 17, 1980.

2. Jorge Chavarro, Walter C. Willett, and Patrick J. Skerrett, The Fertility Diet, McGraw Hill, 2008.

3. Henderson, S. T., "High carbohydrate diets and Alzheimer's
disease," Med. Hypotheses 62: 689-700, 2004.

4. Ursula Dicke and Gerhard Roth, Intelligence Evolved,
pp. 71-77 in Scientific American Mind , John Rennie, Ed. in Chief, Vol. 19, No. 4, Aug/Sept 2008.

5. http://www.westonaprice.org/moderndiseases/
statin.html

6. http://www.cholesterol-and-health.com/
Vitamin-D.html

7. Gary Taubes, Good Calories Bad Calories:Challenging the Conventional Wisdom on Diet, Weight Control, and Disease., Alfred A. Knopf., 2007.

8. http://www.ajc.com/health/content/shared-auto/
healthnews/bird/518293.html

9. http://www.cholesterol-and-health.com/
statins-For-Pregnant-Women.html

10. http://www.autismtoday.com/articles/
Researcher%20sees%20link.asp

11. Rachel Burkert, John McGrath, and Darryl Eyles, "Vitamin D receptor expression in the embryonic rat brain", Neuroscience Research Communications Volume 33, Issue 1 , Pages 63 - 71

12. http://www.autismconnect.org/
news.asp?section=00010001&itemtype=news&id=6066

13. Courchesne E, Carper R, Akshoomoff N., "Evidence of brain overgrowth in the first year of life in autism," Journal of the American Medical Association, July 16, 290(3), pp. 337-44, 2003.


14. http://content.karger.com/ProdukteDB/produkte.asp?
doi=10.1159/000095221

15. C.P. Turner, R. Miller, C. Smith, L. Brown, K. Blackstone,S.R. Dunham, R. Strehlow, M. Manfredi, P. Slocum, K. Iverson, M. West, S.L. Ringler, and Z.C. Berry, "Widespread Neonatal Brain Damage following Calcium Channel Blockade," Developmental Neuroscience, Vol. 29, No. 3, 2007.


http://www.autismcalciumchannelopathy.com/
Genetic_Factors.html

16. Wolf, RL, Cauley, JA, Baker, CE, et al., "Factors Associated with
Calcium Absorption Efficiency in Pre-and Perimenopausal Women,"
American Journal of Clinical Nutrition, 72: 466-471, August,
2000.

17. J. E. Chavarro, J.W. Rich-Edwards, B. Rosner, and W.C. Willett, "A prospective study of dairy foods intake and anovulatory infertility," Human Reproduction (online Journal).

http://humrep.oxfordjournals.org/cgi/content/abstract/
dem019v1

18. http://www.vitamindcouncil.org/health/autism/

19. http://www.marginalrevolution.com/marginalrevolution/
2008/09/the-minnesota-s.html

20. http://en.wikipedia.org/wiki/Cuisine_of_Somaliland

21. http://www.washingtonpost.com/wp-dyn/content/article/2008/
11/03/AR2008110302088.html

22. http://www.slate.com/id/2109131/

23.Greenberg DA, Hodge SE, Sowinski J, and Nicoll D, "Excess of Twins among Affected Sibling Pairs with Autism: Implications for the Etiology of Autism," American Journal of Human Genetics 69:1062-1067, 2001.

http://www.pubmedcentral.nih.gov/articlerender.fcgi
?artid=447617

24. Daniel Redwood, "We Fought Cancer ... and Cancer Won," Newsweek, September 10, 2008.

25. Lange, J.R. et al., "Melanoma in children and teenagers: An analysis of patients from the National Cancer Data Base." J. Clinical Oncology, 2007 Apr 10; 25:1363-8.

26. Joan M Lappe, Dianne Travers-Gustafson, K Michael Davies, Robert R Recker and Robert P Heaney, "Vitamin D and calcium supplementation reduces cancer risk: results of a randomized trial," American Journal of Clinical Nutrition, Vol. 85, No. 6, 1586-1591, June 2007.

27. http://www.vvv.com/healthnews/dsunscre.html

28.Marshall T. G., "Vitamin D discovery outpaces FDA decision making." Bioessays, 30(2), pp. 173-182, Jan 15, 2008.

http://en.wikipedia.org/wiki/Trans_fat

29. http://en.wikipedia.org/wiki/Trans_fat

30. http://www.nytimes.com/2005/02/13/business/
13transfat.html

31. E Fombonne, J Morel, J Macarthur, "No Autism Amongst Inuits From Northern Quebec," Fifth International Meeting for Autism Research, 2006

32. Dr. R. Schechter, "Continuing Increases in Autism Reported to California's Developmental Services System," Archives of General Psychiatry. 2008;65(1):19-24, January, 2008.

http://archpsyc.ama-assn.org/cgi/content/full/65/1/19

http://articles.latimes.com/2008/jan/08/science/sci-autism8

http://www.medicalnewstoday.com/articles/93217.php

33. http://www.whfoods.com/genpage.php?
tname=nutrient&dbid=84

34. http://www.cancer.gov/clinicaltrials/results/
hrt-and-breast-cancer0204

35. http://www.mycentraljersey.com/apps/pbcs.dll/
article?AID=/20080909/HEALTH/809090308/0/ENTERTAIN01


Low-fat Diet and Sunscreen: A Recipe for Disaster by Stephanie Seneff is licensed under a Creative Commons Attribution 3.0 United States License.