Chapter Four

BRAIN-FOOD

Some have described the brain as just an extremely sophisticated computer, predicting that one day, technology will develop to the point where we can simulate the brain, and computers may even gain consciousness. Others argue that while a computer may be a nice analogy for how the brain functions as a system, something else about the brain makes it unique, something which may be impossible to simulate by any computer. Philosophers and science fiction writers can ponder that issue. In the mean time, let us appreciate the human brain for what it is, and how vital DHA is to its healthy structure and function.

Q: What is the brain made of?

A: The brain is made up of the same kind of things that make up any other part of your body: cells. How many? Roughly 14 billion. There are many different kinds of brain cells, and the brain itself is organized into numerous smaller systems, forming a very complex, interconnected system. All together, this relatively small organ weighs only a few pounds and controls every aspect of your life. The cells in your brain have specialized to perform their roles, so brain cells are very different in form and function compared to other cells in the body, say, liver cells. They share many common features, though, and one of the things all cells have is a double layer of lipids surrounding them, the so-called membrane lipid-bilayer.

What might differ about a brain cell's membrane compared to a liver cell's membrane is what fatty acids are used in the lipid-bilayer. In brain cells, 60% of the fatty acids which make up the membrane in the brain is DHA. Moreover, DHA is in the synaptic regions between cells, where one cell sends chemical information to another. This cell-to-cell communication is the fundamental way the brain functions, and your brain is alive with chemical and electrical activity as you read these words. DHA is also found in high concentrations in the sheath surrounding brain cells, the myelin sheath, where DHA may be used as a source of energy. Clearly, DHA plays a major role in the structure and function of the brain.

As we learned earlier, an adequate supply of DHA is vital during the special times when the brain is rapidly forming in the womb, as well as during infancy and childhood. It is also important for the mother, who must be careful to ensure her own DHA requirements during pregnancy and lactation. Moreover, it is important throughout adulthood, since all your cells are continually being maintained by replacing old parts with new ones. In fact, every seven years, you are essentially a completely new person, since in that time, every cell in your body is renewed. Including your brain cells. There had better be enough DHA around to work with!

Q: Can I become smarter by taking DHA?

A: Becoming smarter is difficult to measure. Even the results of standardized intelligence tests may be skewed by cultural and economic differences, not intellectual ones. Moreover, we now recognize many different kinds of intelligence, not just book-smarts, but also physical, emotional, social, and even spiritual intelligence. To call someone "smart" just because he gets A's in school is using a very narrow definition.

If the question is, "Can I improve my concentration, memory, focus, reasoning and problem solving abilities by taking DHA," then some indirect evidence suggests, yes, you can. Certainly, optimal brain function requires optimal health of brain cells. Knowing that the majority of brain cells is DHA, and brain cells are continuously being upgraded with new parts, getting enough DHA simply makes sense. After all, the notion that fish is brain-food must have come from some repeatable observation, as most folk-wisdom does

Previously, we noted that DHA enhanced the problem solving abilities of infants. Later we will consider studies where DHA improved mental function in the elderly. No similar studies have investigated the effects on younger and middle-aged adults. So while we cannot yet say that taking DHA will make everyone smarter, taking DHA might be a pretty smart thing to do. A definitely un-smart thing to do, as far as protecting your brain's DHA, is to drink alcohol.

Q: What does alcohol do to DHA?

A: Drinking even a little bit of alcohol effects the level of DHA in your brain and eyes. The body is extremely careful about DHA, because it is so important to the structure of the brain and other nervous tissue. Researcher N. Salem at the National Institutes of Health reports that in animal studies, rats fed low-fat diets for as long as a year still retain their DHA, but after a single drink of alcohol, DHA levels drop in a matter of hours. The same was found in cats and monkeys. Alcohol immediately leaches DHA out of brain and retinal cells. No wonder alcoholics and chronic, heavy drinkers have been found to be chronically deficient in DHA. They are also prone to other mental diseases such as depression.

Q: Can low DHA levels cause depression?

A: Epidemiological studies (which examine large populations as a whole) find that people in societies which lack fish in the diet suffer from increased rates of depression. Also, recall the earlier discussion of post-partum depression, where a new mother may feel depressed after giving birth. Some experts believe the cause may be due to a depletion of DHA from neuron membranes, the mother's DHA having gone to the fetus for its neural development. Another condition that depletes DHA from brain-cells is alcoholism, with its resulting episodes of depression. Thus, the association between low levels of DHA and depression appears to be real.

A study measuring the DHA levels of depressed people was conducted by Dr. R. Edwards at Northern General Hospital, Sheffield, England. Indeed, he found their red blood cells to be depleted of DHA. Earlier studies correlated the severity of the depression and the ratio ARA to EPA in red blood cells. The worse the depression, the more ARA was present in the blood cells compared to EPA. The researchers suggest increasing this ratio by supplementing with EPA and DHA may be a beneficial strategy in treating depression.

Q: What is the connection between Alzheimer's disease and DHA?

A: Not too long ago, elderly people who slowly lost their memories and mental functions were simply described as becoming senile. If you forget things easily, you might joke you are "getting senile". But getting senile dementia, such as Alzheimer's disease, is not funny. It is a frightening process, which robs an individual a lifetime of memories and dignity. Senility is no longer considered an inevitable part of aging, but rather as a disease which may be preventable and treatable. While much work remains to fully understand the disease, we have uncovered that it is a complicated condition involving many biochemical factors, such as free radicals and how they destroy the DHA in brain cells.

In the effort to understand Alzheimer's, researchers have uncovered some interesting connections with DHA. For instance, Dr. A. Prasad at the University of Kentucky found that Alzheimer's patients had significantly less DHA and other fatty acids in their blood cells. Moreover, Dr. L. Robers at Vanderbilt University discovered that patients with Alzheimer's have very high levels of a chemical known as F4-neuropostanes. These chemicals are actually by-products of DHA oxidation. That is, when DHA is attacked and damaged by free radical oxidation, F4-neuropostanes are left over. These chemicals then may adversely effect brain cell function because their presence changes the normal chemical environment of the brain. So, Alzheimer's patients have not only less DHA, which is vital for proper brain function, but also elevated levels of poisonous, oxidative products, which cause more damage. Adequate antioxidant defenses to protect the DHA seems just as important as the DHA itself.

Q: Can taking DHA improve Alzheimer's?

A: Informal reports by doctors giving senile dementia patients around 700 mg DHA daily are positive. These small-scale trials are based on physician examinations and interviews, which are not objective enough to establish clear conclusions. While these preliminary findings are promising, larger, better controlled studies are necessary before this question can be fully answered. What is encouraging, though, is that taking DHA does not worsen the condition. So, supplementing extra antioxidants, DHA, and other nutritive factors which have positive effects (such as ginkgo biloba), is a sensible strategy for those concerned about this serious mental disease.

Q: What's different about DHA metabolism in schizophrenia?

A: Schizophrenia is a serious mental disorder that interferes with a person's ability to think clearly, manage emotions, make decisions, and relate to others. Symptoms include: hallucinations, delusions, altered senses, an inability to respond appropriately socially or to other exteral stimuli, changes in behavior and emotions, and an altered self-image. It affects 1% of the American population, and its cause is unknown. Researchers are just beginning to explore how a difference in DHA metabolism plays a role in the disease.

Dr. S. Mahadik at the Medical College of Georgia reported that people with schizophrenia do not efficiently convert EPA into DHA. From Chapter One, we learned that an enzyme can make this conversion in normal, healthy cells, thus allowing us to form DHA from a simpler fatty acid. However, the level of this enzyme seems to be lower in cells of schizophreic patients. This finding corroborates a report by Dr. Laugharne at the Second International Congress of the International Society for Study of Fatty Acids and Lipids held in Washington, D.C. Dr. Laugharne gave his patients 10g EPA and DHA and in the course of several weeks noted that as the level of these fatty acids rose in the blood, so did the improvements in schizophrenic symptoms. While these findings are preliminary and much work remains to clarify DHA's role in schizophrenia, DHA and other fatty acids promise to be useful in treating the disorder in the future.

Q: What is DHA's role in the eye?

A: The concentration of DHA in the cells of your eye is even higher than in the brain. Again, DHA is one of the lipids in the protective cell membrane of the special cells in the retina, the rods and cones, which enable you to see. DHA's role in the visual process is to facilitate the rapid signal processing from the eye to the brain. DHA keeps the cell membrane fluid, allowing chemical signals which result from photons of light to pass through it. The cell needs to be able to quickly switch "on" and "off" rapidly to convey these light signals to the brain. Without adequate DHA, the cells do not respond fast enough, and the brain receives inadequate signals. Vision, then, may become impaired.

As we age, our antioxidant defenses become less efficient. The cells in the eyes are particularly susceptible to free radical damage, since a portion of the light from the sun is ultraviolet and x-ray radiation. Without adequate antioxidant protection, the DHA in the eye may be damaged by this high-energy radiation, causing further oxidative damage. Some researchers believe this is one of the reasons why our vision becomes weaker as we get older. For people with an eye disorder called Retinitis Pigmentosa, loss of vision begins much earlier in life, sometimes as early as adolescence. What we learn from this disorder and how it is related to DHA may help us manage the loss of vision that affects many elderly people with otherwise healthy eyes.

Q: What is Retinits Pigmentosa (RP)?

A: Retinitis Pigmentosa (RP) is an eye disease that affects 100,000 Americans. It starts with having trouble seeing at night and other low-lights conditions. Later, peripheral vision deteriorates, resulting in "tunnel vision". Eventually, complete blindness can result. The rate of loss of vision varies among individuals, but usually it is slow, over a period of many years. The disease is hereditary, and more than one family member is usually affected.

Not until recently, doctors could do nothing to help RP patients. Then in the mid-1990's, a study showed that 15,000 IU of vitamin A helped slow down the progression of the disease in some individuals. It was not a cure, but it was the only thing that seemed to help. Since then, researchers have discovered interesting connections between RP and DHA levels. This may lead to developing other treatments for this and other vision disorders.

Q: What is the connection between DHA and RP?

A: Dr. J.Gong and his team at the Lipid Metabolism Laboratory at Tufts University School of Medicine found that overall, RP patients have 10 to 15% lower DHA levels than normal. Even worse, Dr. D. Hoffman at the Retinal Foundation of the Southwest, Dallas, TX, reported those having one form of RP have up to 40% less. Dr. Hoffman also found that the DHA deficiency is easily correctable by supplementation. RP patients were able to absorb and incorporate fish oil fatty acids into their cells as effectively as those with normal vision. On the other hand, when EPA was given, its conversion to DHA was markedly lower than in healthy controls. The ability to enzymatically convert DHA from EPA seems severely impaired. Thus, RP patients need to take pre-formed DHA to effectively raise the DHA levels in their cells to normal.

Q: Can DHA supplementation improve dark adaptation?

A: Just as RP patients have difficulty seeing in dim environments, so do many people suffering from dyslexia, a common learning disorder. In a small study of five dyslexic adults with poor dark adaptation (night vision) and five normal controls, Dr. B. Stordy at the University of Surrey, Guildford, England, gave all subjects the same dose of 480 mg of DHA with no additional vitamin A or D for one month. In four controls, dark adaptation remained the same, as expected, but in one, it clearly improved. (Interestingly, this person was a strict vegetarian, and as we considered previously, vegetarians have lower DHA levels.) On the other hand, dark adaptation consistently and significantly improved in the five with initially poor night vision. While more research needs to be done, DHA promises to be a part of treating vision problems such as poor dark adaptation. Studying how DHA can help optimize our minds and vision has barely begun.