Vitamania by Catherine Price

• many basic facts (e.g. RDI) are not established yet
  
• vitamins are complicated to estimate and measure in human bodies (intraday variation, stored in inaccessible places)
  
• vitamins are complicated and hard to measure in foods (depends on cooking, methods estimate indirectly via bacterial growth)
  

It makes sense, then, that vitamin deficiencies cause problems, because without adequate vitamins, every enzymatic process that depends on those vitamins will come screeching to a stop. In the case of scurvy, the issue is collagen, a primary structural protein in our muscles, skin, bones, blood vessels, cartilage, scars, and other connective tissues that makes up some 30 percent of the protein in the human body. Collagen holds our tissues together; the word itself is derived from the Greek word for “glue.”
Without collagen, our bodies would come apart from within—hence the hemorrhaging, broken bones, and loose teeth of scurvy. We make collagen from its precursor, procollagen, with the help of enzymes. But those enzymatic reactions can’t happen—and thus collagen cannot be formed—without vitamin

And even with that generous built-in margin for error, the Food and Nutrition Board, which is responsible for updating the country’s RDAs, still has not established adult RDAs for biotin, pantothenic acid, or vitamin K, and there are no RDAs for infants up to one year old for any vitamin.

still surprisingly difficult to measure vitamins, whether in our bodies or in foods. Blood tests exist for several, but there are often problems with standardization (that is, results from the same sample can vary from one lab to the next), and there’s continued controversy over what the cutoff for “deficiency” should be. Adding to the challenge, some vitamins are stored in inaccessible places in the body—the most accurate way to measure vitamin A would be a liver biopsy—and our vitamin levels can vary considerably by day or by season depending on what we eat. If you eat a lot of pink grapefruit, for example, your vitamin C level will spike within hours. If you smoke a cigarette, it will drop (as will that of folate). If it’s summertime, your vitamin

Humans and several other simians—along with guinea pigs and fruit bats—are the only mammals that can’t make their own vitamin C.

a popular treatment made from boiled-down citrus juice, had the right idea, except guess what? Vitamin C is destroyed by heat—not to mention cutting, bruising, exposure to air, and being cooked in copper pots.

reactions, as they are in our own. As for plants, their vitamins are entirely self-made: while not every plant makes or needs every human vitamin, in combination, plants naturally make all of the human vitamins except for D, B12, and A. (Plants make beta-carotene, which our bodies can turn into vitamin A, but they don’t make vitamin A itself; some fungi, like mushrooms, can create vitamin D if they are exposed to ultraviolet light, but that usually only occurs if humans deliberately intervene.) Just

This means that the more photosynthesis a plant engages in—whether because it’s located in a particularly sunny location or because its natural pigmentation gathers more light—the higher the levels of vitamins and other antioxidant chemicals that it’s likely to have. The fact that darker colors absorb more light—which is accompanied by higher levels of potentially damaging radiation—is one reason why light-colored vegetables like iceberg lettuce tend to be lower in vitamins and other micronutrients than dark leafy greens such as kale, spinach, and collards. Fruits and vegetables

vitamins, but they lost the ability. This might be because they outsourced the job to plants. For example, humans have the genes necessary for producing vitamin C, but our version contains a disabling mutation that prevents us from actually doing so. Researchers hypothesize that, much like a muscle that atrophies with disuse, this mutation

At the time, food was thought to consist of water and the three macronutrients: protein, fat, and carbohydrate (minerals

explanation for all disease, they now did the same with germs. In many cases, they were successful. But germ theory’s central tenet—that disease is caused by the presence of something—hid the idea that disease could also be caused by something that is lacking.

The terms “polished” and “unpolished” refer to how the rice is milled. In its natural state, rice has a tough, indigestible husk that you need to remove before you eat it. Take off the husk, and you’re left with brown rice, whose color comes from a second interior skin called the pericarp, also known as the polishing. Take off the pericarp, and you’re down to the endosperm—the white, polished rice kernels that we’re familiar with today. Low in fiber and mostly starch, the endosperm’s purpose in the plant is to provide the energy necessary for the rice seedling to grow.

Yet despite its importance—and probably because so many foods naturally contain it—human adults only store about 25–30 micrograms of thiamin in their bodies. Since it has a half-life of between ten and twenty days, thiamin depletion can occur within weeks.

that vitamins existed, the equipment of the day wasn’t sensitive enough to detect them. The amounts of vitamins found naturally in foods are so tiny that even today they’re often quantified by indirect methods—say, by measuring the growth of a bacterium known to be dependent on a particular vitamin—rather than by trying to isolate and weigh them directly.

The boiling was beneficial in that it killed some of the deadly microbes that were responsible for the era’s high death rate of children raised on (contaminated) cow’s milk. But the heat also destroyed the mixture’s vitamin C.

(As a reminder, enrichment generally means replacing micronutrients that processing has destroyed; fortification means adding micronutrients at higher amounts than were originally present or introducing micronutrients to foods that never naturally contained them.)

Vitamin A is stored in the liver, and most well-nourished people have enough to last up to a year. That’s why it often took sailors longer to develop night blindness than scurvy: unlike vitamin A, the body doesn’t have a significant reserve store of vitamin C.

“Then the next argument was, ‘Parents like an injection.’ I said, look, fine, give them an injection, too. The problem is that no one’s going to have water-miscible vitamin A on hand because it’s expensive. What they’re going to have is what they have now: oily vitamin A. And if the recommendations say the kids need an injection, then they’re going to give them an oily injection and think they’ve done the job and the kid will go blind.” It was a situation that’s still common in medicine today: parental desires can negatively influence doctors’ treatment decisions (such as when people demand antibiotics for viral infections, which antibiotics can’t cure), and the medical establishment can be slow to change treatment recommendations based on the latest science.

The Lancet published these findings in 1986, with an accompanying editorial of support. This time the medical and nutritional communities paid attention—and they weren’t pleased. Angry letters to the editor poured in criticizing both Sommer and his studies. High doses of vitamin A can be dangerous, they said. He hadn’t used a placebo control. And, most of all, his conclusion—that providing sufficient vitamin A might prevent 34 percent of deaths in deficient kids—was just too good to be true.

“Extra vitamin A doesn’t do anything if you already have enough of it,” Sommer explained. “But they were giving vitamin A like you’d give antibiotics, thinking it’d affect everyone the same no matter how much vitamin A they already had.” (This is an important point: vitamin A will only help your immune system if you are extremely deficient in vitamin A, which very few Americans are, and it is toxic at high doses. Do not start taking high doses of vitamin A.) Sommer’s comment also touched on the other likely cause of the mass amnesia surrounding vitamin A and immunity: antibiotic drugs. The first antibiotics were developed in the 1930s and 1940s, and unlike vitamin A, which only produces marvels when a patient is already deficient in it, antibiotics’ effects against bacterial infections were immediate, consistent, and astounding. The possible role of a vitamin as a preventive agent paled in comparison with antibiotics’ curative powers.

contain much oil, like a leaf—the conversion is far less efficient. The WHO tries to take this discrepancy into account by using a conversion factor of 6 molecules of beta-carotene to 1 molecule of vitamin A. In the United States, the Institute of Medicine has settled on a conversion rate of 12–1. But in reality, the amount of beta-carotene we convert to vitamin A from most plants is far lower. “What the researchers found is that if you feed someone a fruit that’s rich in beta-carotene—papaya, mango—it takes about 18 molecules, not 6, to get one molecule of vitamin A,” said Sommer. “And if it’s a dark leafy vegetable like spinach, it takes about 27 molecules of beta-carotene to make one of vitamin A. So if you put together what a kid might get from fruits and leafy vegetables, it’ll take about 24 molecules of beta-carotene to make one molecule of vitamin A.” Other recent papers have come up with slightly different conversion factors, but the basic range is the same.

Perhaps most important, there are times when traditional breeding techniques simply won’t work. Bananas, for example, are nearly impossible to breed because the ones we like to eat don’t contain viable seeds. (Those little black dots in their flesh are undeveloped, defective seeds: they possess three chromosomes instead of two, which prevents them from fully forming.) Without seeds, a plant can’t be conventionally bred—which means, obviously, that you can’t introduce new traits through conventional breeding. In other cases,

successful)—they had created rice plants whose endosperms contained beta-carotene. The yellow-orange color of the grains, which was caused by the beta-carotene, inspired its name: golden rice.

Golden rice contains no added pesticidal or herbicidal properties. Nor is it likely to be toxic: beta-carotene is not allergenic, and while large doses of vitamin A can indeed be quite dangerous, our bodies are wise enough to know when to stop converting beta-carotene when vitamin A levels get too high.

and routinely consuming too much vitamin D can lead to dangerously high blood calcium levels and eventually cause calcium deposits in places you don’t want them, like your arteries or kidneys.

They can be destroyed by heat, air, moisture, pH, light, or even simply the passage of time. Vitamin C is particularly challenging: it’s sensitive to everything. This is why many fortified foods and vitamins contain “overages” (that is, more micronutrients

diseases like cancer and heart disease. This is known as oxidative damage, or oxidative stress. Antioxidants like beta-carotene and vitamins C and E are special sorts of molecules that are able to donate an electron without becoming unstable themselves, thereby stopping potentially dangerous chain reactions before they get out of hand.

found no benefit or harm from beta-carotene supplementation, even among the smokers. Overall, the results were inconclusive at best: of the original five large studies on beta-carotene, one had been slightly positive, two had been alarmingly negative, and the other two were neutral. The general consensus today is that large doses of beta-carotene are not beneficial—and are potentially dangerous, especially for smokers.

many vitamins do similar things for plants that they do for our own bodies, and the only human vitamins that plants cannot produce in notable quantities are vitamins D, A, and B12. (It’s also worth noting that animal products contain all vitamins in reasonable quantities except for vitamin C.) It’s the potential actions of

compound is necessarily safe. The effects of some compounds also depend on what else they’re consumed with—the fat-soluble vitamins (A or beta-carotene, D, E, and K) require adequate fat to be absorbed (that’s one reason cooking vegetables with oil can make them more nutritious), whereas the water-soluble vitamins (C and the Bs) do not. What’s more, whole foods often appear to contain other substances that are necessary