Health column by Dr. Greg Feinsinger. Champion of Whole Food Plant Based Living and righteous person.
Humans evolved to meet all their nutritional needs, including vitamins and minerals, through the food they eat—not by taking supplements. In modern life however, there are two exceptions: vitamin B12 and vitamin D.
A recent column discussed vitamin B12, and how it is made by bacteria in dirt. Over millions of years of human evolution there was plenty of dirt in the food humans ate. And there is still dirt in what animals eat, and B12 is stored in their flesh. People who eat animal products get adequate B12 until they reach the age of 50, after which the ability to absorb B12 diminishes. Given treated water and pre-washed produce, people who don’t eat animal products can develop dangerous B12 deficiency, and it is IMPERATIVE that all vegans and vegetarians of any age take daily B12 supplementation.
In the recent B12 column, requirements for different age groups and for special populations such as pregnant and breast-feeding women were discussed. A clarification needs to be made about recommendations toward the end of that column: 1) Due to decreased absorption, people age 50 to 64, no matter what their diet, need to supplement with 50 mcg of (micrograms) of B12 a day. 2) All people age 64 and above, no matter what their diet, need to supplement with 1000 mcg. of B12 a day.
Vitamin D is called the sunshine vitamin because, although some foods have small amounts, most of our vitamin D comes from interaction of sunlight with our skin. Vitamin D helps our body absorb calcium, and is therefore important bone health. Ricketts is a bone disease caused by lack of vitamin D, and in 1822 a Polish physician showed that Ricketts can be prevented and treated with sunlight. Like many medical discoveries, this one got buried for a century, when—in the early 1900s–wire cages were attached to tenement windows to expose young children to sunlight.
Until the industrial age, people spent more time in the sun than most do these days. Furthermore, for skin health, many people cover their skin with clothing and/or sunscreen when outside. So, vitamin D supplementation is necessary for most of us. According to Dr. Greger in nutrtionfacts.org, the amount of D supplementation needed for bone health is 600 international units (i.u.) per day for people age 1 to 70, and 800 i.u. over age 70.
Observational studies have suggested that vitamin D supplementation has many additional health benefits, but these types of studies aren’t acceptable as proof. The one health benefit of vitamin D that has been proven with well-done randomized studies is a decrease in all-cause mortality (i.e. prolongation of life). The amount of D supplementation to achieve this is 2,000 i.u. a day for adults, so that is what Dr. Greger recommends. There are two types of vitamin D, D2 and D3—and D3 is what you should take for supplementation.
There is such a thing as too much vitamin D, and over 4,000 i.u. a day and above can be toxic. Dr. Greger doesn’t recommend testing vitamin D, in part because of variability in test results (e.g. results can vary widely if the same specimen is sent to different labs).