When I was a medical intern I watched my supervising resident perform an immediate and visible cure and in that moment understood the appeal of vitamins to our pill-loving culture. We were laboring over an old gentlemen brought to the emergency room from Boston’s Commons – a park that was home to many people whose diets came largely from brown-bagged liquor bottles. Our patient was agitated and confused. Try as we might we could not get his eyes to move in any direction. My resident disappeared and returned with a tiny syringe filled with a Vitamin B1, also known as thiamine. He injected the liquid into the patient’s vein and, as if he’d waved a wand, our patient’s eye movements returned and he calmed down. Here was a miracle drug, and it was something nature made for us.
The magic of our patient’s recovery was a clear example of the function of vitamins. In minute amounts, they act as facilitators of chemical reactions necessary for energy production and cellular maintenance of all kinds. Our patient had a textbook case of vitamin deficiency, the result of a very bad diet or failure to absorb vitamins from the stomach and small intestine, or both. Alcoholism is the most common setting, but vitamin deficiencies occur with other severe gastrointestinal problems and in the malnutrition associated famine or devastating illness like cancer and AIDS. Sometimes medical treatment itself is the perpetrator, in the form of anticancer drugs or bypass surgery for morbid obesity.
For thousands of years, people have understood that certain foods contain substances vital to human life. The ancient Egyptians recognized that night blindness was cured by eating liver. In the 1700s, seagoing men found that lime juice prevented scurvy – the aches, skin rashes and loss of teeth from painful gum disease that occurred when men attempted to live for months without fresh food. When the nature of food’s magic yielded to chemical analysis, scientists found complex molecules with many active forms that acted as co-factors or triggers in energy-producing chemical reactions in all cells of the body. They were also involved in cell maintenance and reproduction.
Naming the magic
Chemists named the indispensible compounds vitamins (vita: root word for life; amine: a chemical group containing nitrogen, which early studies suggested all vitamins contained) and tagged them with letters as well as chemical names (see list below). Vitamins F – K eventually became part of the large Vitamin B complex group, and some vitamins were downgraded to “vital nutrients.” Synthetic vitamins appeared on store shelves, joining age-old remedies like cod liver oil, yeast and wheat germ. But even in our times, the best source of vitamins remains the whole foods in which nature embeds them with other factors that we may not yet recognize as important.
Water soluble vitamins
The B vitamins and Vitamin C dissolve in water. They aren’t stored in the body and can be lost or inactivated by cooking. These water-soluble vitamins find their way to their target cells, get used, recycled a bit, and then find their way out of the body in the urine. They need to be eaten on a daily basis. You cannot overdose on B vitamins in food, but very high doses of B vitamin pills can damage the nerves.
Fat soluble vitamins
Fat-soluble vitamins (A, D, E and K) accumulate in liver and fat tissue, ready to be used when necessary, but damaging if too much is stored. Some Arctic explorers died of brain swelling from consuming polar bear liver, very high in Vitamin A. Too many carrots (source of carotenes, or pre-Vitamin A) cause yellow skin. Too much Vitamin D raises blood calcium levels, producing weakness, lethargy and kidney stones. Vitamin K can interfere with Coumadin, a medicine used to prevent blood clotting, so patients are cautioned to eat only small amounts of very flavorful greens like Kale and collards.
If you are not alcoholic or malnourished from serious illness, if you live in a western countries where vitamin fortification (enrichment) of common foods is the routine, if you eat well-balanced meals drawing fresh food from plant and animal sources, if you are meeting your energy needs and not trying to lose weight by restricting calories, and if you get enough sun exposure, you do not need any vitamin pills. Vitamins are best absorbed from real food.
In our current eating culture, however, a couple of vitamins do warrant concern. Folate (Vitamin B9) consumption, vital to cell replacement, is inadequate when fruits and vegetables are not chosen or hard to come by. Vitamin D deficiency, which became rare when fortification of milk began, is again on the rise, producing rickets (malformed bones) in children, weakened bones in adults, and weakened immune systems in all age groups. Cholesterol phobia makes people avoid good Vitamin D sources like whole milk and egg yolks. Sun exposure of head and arms for just 15 minutes 2 or 3 times a week makes enough Vitamin D in skin to our needs, but effective sunscreens and lack of outdoor activity have put serious dents in sun exposure.
What about Vitamin C, the wonder vitamin? Most plants and animals make it. We do not. Linus Pauling, Nobel prize-winning chemist, speculated that our intake should be much higher than the small amount required to prevent scurvy. Apes, who’ve also lost the ability to make Vitamin C, consume 10 -20 times as much as we do. Goats, who make Vitamin C in huge quantities, make even more when stressed. Does Vitamin C help prevent colds, strengthen our connective tissue, and get used up faster in times of physical stress? Maybe. We just don’t know. But in the meantime, large doses, up to several thousand milligrams per day, appear to do no harm. (Smokers do need extra C.)
Take advice with a grain of salt
What are we to think of all the articles we see extolling the virtues of this vitamin or that in preventing this disease or that? Be wary of these words: suggests, indicates, may be, could prevent. If any of the putative effects were as clear as our emergency room patient’s revival, or the salvaging of sailors’ gums and teeth, or the cure of the Egyptians’ night vision, we would not be using tentative words. Keep your focus on a fresh food diet that excludes no food group, and on the physical activity that enables you to eat enough food to get everything you need without getting fat. Take Vitamin C if you want to, and add a multivitamin from a reputable company if you are dieting or restricting your diet in any way, or don’t like vegetables and fruit.
Major Vitamins and Some Food Sources
(RDA) Recommended daily allowance
|Vitamin A||(retinol, retinoids
|Beef and chicken liver*
Whole milk, eggs, cheese
|Carrots, spinach, yellow vegetables and fruits|
|Vitamin B1||Thiamine||1.2 mg
|Pork*, lean meats, fish||Brewer’s yeast*, wheat germ*, whole grains
Enriched grains, legumes, nuts
|Vitamin B||Riboflavin||1.3 mg||Eggs, lean meats, milk||Brewer’s yeast*, cereals, nuts, leafy greens|
|Vitamin B3||Niacin||16.0 mg||Lean meats, poultry, fish, eggs||Beets, Brewer’s yeast*, peanuts, other nuts, sunflower seeds, green leafy vegetables, coffee, tea|
|Vitamin B5||Pantothenic acid||5.0 mg||Calf’s liver*, eggs, yogurt||Brewer’s yeast*, whole grains,sunflower seeds, mushrooms, squash, cauliflower, broccoli|
|Vitamin B6||Pyridoxine||1.3-1.7 mg||Liver, egg yolks, poultry, fish||Wheat germ, whole grains, peanuts, walnuts, bananas, avocados|
|Vitamin B7||Biotin||30.0 µg||Eggs yolk, liver||Brewer’s yeast, wheat bran cauliflower, avocado|
|Vitamin B9||Folic acid||400 µg||Beef liver*, egg yolk||Fortified cereals*, leafy green vegetables, citrus fruits|
|Vitamin B12||Cyanocobalamin||2.4 µg||Meat, eggs, dairy products, shellfish, salmon||Fortified plant milks and cereals only. No natural plant sources.|
|Vitamin C||Ascorbic acid||90.0 mg||Citrus fruits*, tomatoes, berries, green and red peppers, broccoli, spinach|
|Vitamin D||Ergocalciferol and
|5.0 µg-10 µg||Dairy products, salmon, tuna||Fortified cereals|
|Vitamin E||Tocopherol and
|15.0 mg||Wheat germ oil*, almonds*, hazelnuts,sunflower seeds and oil, safflower oil|
|Vitamin K||Naphthquinone||120 µg||Broccoli*, Kale*, Swiss chard*, soybean oil*, canola oil, olive oil|
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