In the last post, I have tackled carbohydrates in vegetables and fruits. However, the rationales behind eating whole vegetables and fruits are mainly the benefits of vitamins, minerals, and other nutrients. This post continues the previous discussion by focusing on vitamin supplements.

Vitamin supplement has been a controversial topic for a long time. Almost all people who discovered vitamins won Nobel Prize. 20 years ago, any positive results of vitamin supplements might land on prestigious journals such as New England Journal of Medicine (NEJM). 10 years ago, many negative results also appeared in NEJM. Now, people got so tired of all these confusing messages that a recent meta-analysis of vitamin E was published in an obscure British journal.

On the other hand, almost 40 years after Linus Pauling’s promotion based on his good faith, the US spends $6 billion a year on variety of vitamin supplements. It seems that people just take it no matter what.

The debates on the usefulness of vitamins center on Vitamin A, C, and E, the magical antioxidants. News media make the word “antioxidant” housewife’s vocabulary now. However, unless you have some knowledge of biochemistry and pathophysiology, you probably have no idea why antioxidants are good for you.

Let me give a heuristic explanation. The way our human body uses energy is to burn glucose or fat to generate ATP, the energy currency inside cells. The furnace is mitochondria, a small gadget our cells captured during the evolution. After glucose or fat enter mitochondria, some enzymes break down carbon and hydrogen chains; protons are then used to generate ATP. Remember, protons (positive) and electrons (negative) are pairs. Since we have used up protons for ATP, the extra electrons will generate by-products–reactive oxidative species (ROS) such as free radicals and superoxides. They are very active, ready to oxidize anything they encounter. For example, when ROS meet with low density lipoprotein (LDL, the bad lipoprotein), it can oxidize LDL. The ox-LDL will attract macrophages to clean the mess. The LDL-loaded macrophages become foam cells in the blood vessel layers, thus forming atherosclerosis. Therefore, eliminating ROS or blocking the oxidation will lower the oxidative stress, reducing the risk of heart diseases. Furthermore, since ROS can damage cells or proteins, anything that can stop oxidation may also prevent cancer and delay aging.

From the very beginning of human history, people have frantically searched for magic antidotes to counter diseases and hope to live forever.If the above oxidation theory is true, what else could be better than antioxidants?

Vitamin A, C, E are such antioxidants, readily available in our daily diet. They have also been synthesized as pills to satisfy human needs. A small pill per day will have more than enough antioxidants, together with other vitamins and minerals for your body.

The disturbing fact is that many random-controlled studies suggested that extra vitamin A and E intake had no effects on your health. Even worse, some studies showed that a mega dose intake of beta-carotene might increase the risk of lung cancer among smokers. Recent meta-analysis also suggested that mega-dose of Vitamin E might lead to more deaths. In addition, a high dose of vitamin C will generally be unnecessary because vitamin C is water soluble. Extra vitamin C will simply be flushed away.

Nevertheless, people will not be deterred by these arresting results. The oxidation theory is just too beautiful. Anyway, you only need very little of something to do the fighting. If beta-carotene or vitamin E do not work, something else may work. For example, recent fashion is to take pills with lycopene, which is abundant in tomatoes, or “A to Z” nutrients as Centrium has advertised. I also know some people are conducting feeding studies on flavonoids, which is widely available in fruits and tea.

However, if all antioxidants are widely available in vegetables and fruits, and if the combination of antioxidants in natural foods is probably optimal because human body is geared towards these foods by evolution, and if there are other unknown antioxidants, anti-cancer, or anti-aging stuff in the natural foods, why don’t we just eat sufficient and various vegetables and fruits? We can plainly forget about all those vitamin supplements.

Bible doesn’t tell us what kind foods Adam and Eve consumed in the Eden. The only fruit mentioned is the forbidden apple. However, I think their diet must include a variety of vegetables and fruits because they live in the forest and was supposed to live forever. We should find a way to go back to that forest and live happily ever after.

Let’s go back to the jungle!