Vitamin B5 (Pantothenic Acid)
Pantothenic acid is essential for human health, but it is so widely available in so many foods that it’s practically impossible to find anyone who has a deficiency.
To prove that pantothenic acid is a vitamin, scientists had to feed volunteers a special purified diet that was artificially low in pantothenic acid.
Even then, it was hard to sort out what problems resulted from the lack of pantothenic acid, and what problems resulted from some other abnormality of the diet.
In short, pantothenic acid deficiency is nothing to worry about.
Vitamin B6 (Pyridoxine)
Pyridoxine (vitamin B6) is found in a wide variety of foods.
A deficiency of pyridoxine is extremely rare, even in poor countries.
However, it can be caused by the use of some drugs that increase the body’s requirement for the vitamin. Examples include the tuberculosis drug isoniazid.
There are also some rare genetic disorders that increase the person’s requirement for pyridoxine.
Vitamin B7 (Biotin)
Biotin deficiency is also extremely rare because we generally get more than enough of this vitamin from the bacteria in our intestines.
To study the effects of biotin deficiency, scientists had to feed volunteers large amounts of raw egg white for a long period.
Raw egg white contains a substance called avidin that binds to biotin, keeping it from being absorbed.
Other cases of biotin deficiency occurred in patients who were being fed intravenously before biotin was added to the intravenous feeding solutions.
Vitamin B9 (Folate)
A deficiency of folate (vitamin B9) causes a form of anemia that looks a lot like the pernicious anemia that results from vitamin B12 deficiency.
Unlike pernicious anemia, however, the anemia related to folate deficiency was common among poor pregnant women in India in the 1930s. It was also found in British patients with digestive diseases, such as celiac disease.
A commercial yeast extract called Marmite, which was widely used as a dietary supplement, rapidly cured the problem.
The nutritional factor responsible for curing the anemia was eventually found to be a form of folic acid, which was originally isolated from spinach leaves.
Folic acid, as such, does not normally occur in nature. Folic acid is a fully oxidized version of the chemically more complicated folates that are found in leafy greens and many fruits, such as oranges, tomatoes, and cantaloupes.
However, the oxidized version is more stable, which is why it is the form that is used as a food additive and in vitamin pills.
Vitamin B9 provides another example of why it’s better to get your vitamins from food than from supplements, and why the use of supplements can have risks as well as benefits.
The story is a bit complicated. I’ll just give you the highlights.
In 1998, the FDA started requiring folic acid to be added to enriched grain products. The goal was to eliminate folate deficiency in women who might become pregnant, thus reducing the risk of serious birth defects of the spinal cord or brain.
The damage occurs very early, before most women even know that they are pregnant. Adding the extra folic acid to the food supply has substantially reduced the number of babies born with these defects, but it raises concerns about pernicious anemia and other health problems.
Although folic acid can be used to meet the body’s need for folate, the human body does not handle folic acid in the same way that it handles naturally occurring folates.
If you take too much folic acid, you overwhelm the body’s ability to convert it to its natural form. Thus, you can end up with some of the unaltered oxidized form of folic acid in your system, which could have unwanted effects.
Nutrition experts are also concerned that folic acid supplementation could hide the evidence of pernicious anemia, which is a potentially deadly disease.
The extra folate might cure the telltale blood disorder associated with vitamin B12 deficiency—but without preventing the vitamin B12 deficiency from causing permanent nerve damage.
In other words, the person could be suffering progressive, permanent damage to the brain and spinal cord without having any early warning signs. This wouldn’t be a problem if people were being monitored for vitamin B12 deficiency, but many people are not.
People who don’t eat animal products probably should get their vitamin B12 levels checked periodically, as should elderly people.
There are also important concerns that abnormally high intakes of folic acid could increase the risk of heart disease and cancer.
In contrast, people whose intake of natural folate is high because they eat lots of vegetables and fruits have a low risk of heart disease and cancer.
The folic acid supplements are found in foods made from refined grains. If you eat whole-grain foods instead of refined foods and eat lots of leafy
Vitamin B12 and Pernicious Anemia
The only true vitamin that is not made by plants is vitamin B12, which is made by bacteria.
A deficiency of vitamin B12 causes a potentially deadly disease called pernicious anemia. However, most diagnosed cases of pernicious anemia result from an inability to absorb the vitamin from the food, not from the lack of the vitamin in the diet.
Because plants don’t contain vitamin B12, people who stick to a purely plant-based diet for any length of time are generally advised to take a vitamin B12 supplement.
It may take up to 3 years for a person’s vitamin B12 stores to run out. Even so, a study of people who had supposedly been following a purely plant-based diet for years found that they didn’t necessarily have a vitamin B12 deficiency. Still, it is better to be safe than sorry.
A deficiency of vitamin B12 can cause not only anemia but severe, permanent damage to the central nervous system. If people eat a lot of folate or take a folic acid supplement, they might end up with the brain and nerve damage without getting anemia first as a warning sign.
There has been a lot of discussion about alternative sources of vitamin B12 for people who don’t eat animal products.
One problem is that the test that is normally used to measure the amount of vitamin B12 in foods can sometimes react to substances that do not have vitamin B12 activity in the body. To be on the safe side, just take a proper vitamin B12 supplement.