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January 11, 2010
Brain Boosters

One of the defects often found in published research is that the effort to do controlled experiments excludes relevant variables.

For decades, omega-3 fatty acids have been praised for their myriad health benefits. Credited with helping treat or prevent degenerative illnesses such as heart disease, rheumatoid arthritis, diabetes, and even Alzheimer's disease, they also play a key role in brain development and cognitive function. . .

In humans, omega-3s are essential fatty acids that are necessary for health, but cannot be manufactured from scratch by the body. They are obtained largely from fish and other marine organisms, such as algae and krill. The body uses several types of omega-3s, including two "fish oils": eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). "DHA and EPA sit atop a hierarchy of omega-3s and provide the most clear health benefits," . . .

While other oils are used in membranes all over the body, omega-3s are far more specific in their location. They are found most predominantly in the brain, in the eyes, in certain other brain-like cells, and in sperm, according to David Valentine. "They are precisely targeted," he said. "And the reasons for that are twofold. Their physical and chemical properties enable specialized cellular functions, such as the rapid firing of neurons and the rhythmic pulsing of sperm tails. However, omega-3s are so chemically unstable that they oxidize and go rancid very quickly, and are therefore excluded from all other cells."

That instability, he added, is their down side. "The brain is absolutely packed full of omega-3s. However, there's also oxygen in the brain, and that's going to cause a reaction. They're going to oxidize. And that gradual oxidation is, in essence, a losing battle against brain damage. After a lifetime, the damage takes its toll," he said.

I think that in the history of the human species and most other animals - all of which need omega-3s - not much came from fishes, algae or krill. They got them from a food chain that begins with shorter chain omega-3 fats in plant leaves - grass and such - which are partially converted to the longer chain omega-3s DHA and EPA - the true issue here. Each step up the food chain concentrates the long chain omega-3s. A chicken that eats an insect that had eaten leafy vegetation gets a more concentrated dose. The human that ate a goat - or drank its milk - that had browsed and grazed all of its life got a concentrated dose. If the milk was made into cheese the concentration increased.

This isn't just a correction of the misleading idea that sea life is necessary in the human diet. The long chain omega-3s aren't the only valuable nutrients contained in these foods. CLA - an omega-6 fat - is also present in the goat milk and flesh, and it has antioxidant properties. Vitamin E is another anti-oxidant also present in quantity. But it get even weirder. CLA is itself subject to oxidation and becomes a radical that damages cancer cells through lipid peroxidation, a cytotoxicity apparently specific to cancer cells.

I'd like to see research by more well informed scientists who understand more about dietary sources of nutrients and their combined effects. It is a truism that balance matters greatly. Many beneficial nutrients are harmful in excess, and excess is often defined as the lack of other related nutrients. It's not just that the dose makes the poison, it is also that other ingredients make or break the poison.

Despite the hazards posed by a lifetime of omega-3s, Valentine does not encourage people to toss out their bottles of fish oil. In fact, the contrary is true. "I consume plenty of DHA because I think the benefits to human health far outweigh the down sides," he said. "There's no question, for example, that omega-3s help brain development in children. The brain relies heavily on DHA, and will perform better when it is plentiful," he said. "But it's an inevitable catch-22. Human intelligence is derived in part from DHA, but DHA itself is inherently unstable."

The effects of omega-3 oxidation are, in some ways, a function of the ever-increasing human life span. "The dangers have never been an issue in human evolution because humans didn't live to be 70 or 80 years old," said Valentine. "There was never this wall that people would hit, because they didn't live that long."

For the time being I'm comfortable getting my DHA and EPA from ruminant milk and meat since it also has the CLA and vitamin E antioxidants that are beneficial for many other reasons, and may perhaps even help with the omega-3 oxidation problem.

Update: Which vitamin E?

Vitamin E occurs naturally in eight different forms. The best-known form of vitamin E belongs to a variety called tocopherols. The form of vitamin E in this study, tocotrienol or TCT, is not abundant in the American diet but is available as a nutritional supplement. It is a common component of a typical Southeast Asian diet.

Sen's lab discovered tocotrienol vitamin E's ability to protect the brain 10 years ago. But this current study offers the most specific details about how that protection works, said Sen, who is also a deputy director of Ohio State's Heart and Lung Research Institute.

"We have studied an enzyme that is present all the time, but one that is activated after a stroke in a way that causes neurodegeneration. We found that it can be put in check by very low levels of tocotrienol," he said. "So what we have here is a naturally derived nutrient, rather than a drug, that provides this beneficial impact."

It seems to me that we sometimes have more knowledge of and concern for the diets that we give to our livestock than to ourselves. I know, there is a minority that cares deeply and pays close attention to human nutrition, but data about the relative abundance of the various vitamin E forms in different forages seems more readily availble than for foods in human diets.
Posted by back40 at 02:14 PM | Health

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