Why Is Choline Important In Our Diet?

In 1844, a substance, that came to be called lecithin, was isolated from the yolk of an egg. The word, “lecithin,” is derived from the Greek lekithos, which in fact means egg yolk. A few years later, in 1849, a German chemist extracted a related material from hog bile, which he later called “choline,” after the Greek word chole, meaning bile. Choline is the chemical backbone of lecithin.

What is choline and what is its importance to human nutrition? Choline meets most all of the criteria to be called a vitamin, although the body can generate generous amounts. Its absence in the diet may lead to certain specific deficiency conditions, especially in experimental animals, although its vital importance as a nutrient intake for humans is debated because the body can make plentiful amounts under most conditions. Basically, though, we need choline in much greater amounts than we do most vitamins.

Choline has several important roles in the body. A key function involves nerve tissues and, especially, the brain. Indeed, choline is an integral structural component of nerves. Choline also combines with acetate to form acetylcholine, a neurotransmitter that helps the electrical current of messages “jump the gap” between individual nerve cells.

In the middle of the last century, during the Korean conflict, doctors conducting autopsies on battlefield casualties were shocked to discover that the major blood vessels of many young soldiers killed in battle were lined with cholesterol-containing fatty streaks and atherosclerotic plaques. It had been taken for granted that atherosclerosis, or “hardening of the arteries,” was a natural consequence of ageing and was generally expected to be found in older individuals. It was, at the time, a totally unexpected finding to encounter early hardening of the arteries in 18-year-old, otherwise healthy young men.

These results, as well as other observations at the time, led to a massive public health campaign to reduce cholesterol intake in the American diet. Over the second half of the 20th century, bit by bit, dietary cholesterol intake fell, individually and in the general population at large. There were many sources of cholesterol in the diet that were reduced or essentially almost entirely eliminated, but perhaps none more so than eggs. People went from consuming several eggs per day, as our grandfathers or great grandfathers once did, to only a few or almost no eggs per week.

What effect did this progressive reduction in cholesterol have on health and disease? Blood cholesterol levels fell, as did the occurrence of some cardiovascular diseases. A curve charting the reduction in egg consumption versus time over the second half of the last century, however, can be matched, as a mirror image, with the increase in what was once a relatively uncommonly recognized disorder, Alzheimer’s disease. We now have an epidemic of Alzheimer’s disease, whereas in the middle of the 20th century it was a condition that was infrequently diagnosed. Even the best of what are now “old time” doctors say that at that time they just never saw Alzheimer’s disease, and it is unlikely that they just missed it.

Does this mean that Alzheimer’s disease is due to a lack of egg yolks, or choline, in our diet? Egg yolks, after all, are the primary, and from a practical sense the almost exclusive, source of dietary choline. It is hardly as simple as that, however, although the administration choline in “therapeutic doses” has been at times a treatment for Alzheimer’s disease, especially not too long ago before some of the more modern therapeutic pharmacologic agents became available.

Addressing these considerations is not an easy task. The body’s requirements for choline is influenced by the amount of the amino acid methionine we have available, as well as by the amount of folic acid and vitamin B-12 in the diet, the growth conditions of individuals, energy intake and energy expenditure, the amount and type of dietary carbohydrate consumed, the total amount of protein in the diet, as well as the type and amount of fat, including cholesterol, and several other factors. So, these are very complex interactions, but so too is the origin of Alzheimer’s disease.

Alzheimer’s disease is one of the most feared of medical disorders, perhaps now even more so than cancer. The number of individuals with Alzheimer’s disease numbers in the million, mostly in older ages. The older you become, the greater does the risk increase. But more than 500,000 people in this country under the age of 50 years of life have been diagnosed with Alzheimer’s disease, as have another 500,000 between the ages of 50 and 60 years. The disease may come on slowly or more suddenly. It is always fatal and, as yet, never curable. It is devastating to the person affected, as well as to their families and to society as a whole. It may last for years or the end may mercifully come quickly.

How much choline do we need in our diet? The answer is not known, but it is estimated that the average intake now for an American is about 400 to 900 milligrams per day. Where do we get dietary choline? Beyond egg yolks, we do not find it in very many sources. Beef, pork and lamb livers are reasonable sources but those are hardly household staples. Some choline is found in soybeans and soybean products, dehydrated potatoes, alfalfa leaf meal, dried buttermilk and dried skim milk, rice polish, navy beans, rice bran, sorghum, and blackstrap molasses, but who among us eats any of these? You can also take choline as a dietary supplement, prescribed or otherwise.

The diminished intake of dietary choline, through a reduction of the intake in egg yolks as a consequence of the anti-cholesterol campaign, is but a theory, among several theories, on the origin of Alzheimer’s disease. This has caused some to question have we but just simply exchanged one disease (atherosclerosis) for another (Alzheimer’s disease)? Ultimately, we will better understand what causes Alzheimer’s disease and why we now have a major epidemic of a very terrible condition. We will have to wait for those scientific answers, but in the meantime some of us have gone back to eating more eggs than we once did.

Dr. Huber is the director of the Texas Nutrition Institute, a not-for-profit program serving the needs of the people of East Texas. Do you have a question or a topic idea for Dr. Huber? Email him at huber1997@aol.com.

Source: tylerpaper.com