Vitamins are critical for our health, and there are 12 known essential vitamins. Vitamins can only be acquired from the diet or supplements and work by acting as “cofactors” (enablers) for some enzymes. These enzymes can’t work properly without their cofactors. Enzymes are proteins that are like little machines in our cellular factories that allow molecules to either be built up or broken down according to our bodies’ needs. There are thousands of enzymes.
Vitamin D was originally thought be a vitamin, but it turns out it is not. It never acts as an enzyme cofactor. It is a hormone. What’s the difference?
Hormones are molecules (made by enzymes, like everything else) which are secreted into the blood and carry messages to other cells, telling those cells to do things differently than if the hormone wasn’t present. A good example is epinephrine or adrenalin. It is secreted by the adrenal gland and goes to other areas of the body where it stimulates a fight-or-flight response – dilated pupils, increased breathing, increased heart rate and blood pressure, etc.
Vitamin D is a hormone which is manufactured in several different tissues. Initial synthesis starts in the skin where cells harness energy from the sun (ultraviolet B rays) to break a bond in the cholesterol molecule, which is the backbone for all steroid hormones. This is the only known instance of an energy source outside of your body being required to manufacture a molecule!
Once the skin starts the manufacturing process, it is finished in the liver, kidney, and other cells in the body until vitamin D is finally in its fully active form. What does this hormone do? Many things – it allows your intestine to absorb critical minerals such as calcium so that bones can be built and maintained. It also plays a critical function in your immune system. Your immunity is weak when vitamin D is low, which is likely why people tend to get sick more often in the winter – less sun, less vitamin D, less immune function, more illness.
Vitamin D appears to influence about 20% of all the genes in your body. That is a massive impact compared to many other hormones!
One of the more important vitamin D functions we have found recently relates to mood. Your body cannot make adequate amounts of serotonin without vitamin D. Serotonin is needed for a good mood, and serotonin deficiency causes depression. Serotonin is also necessary for the synthesis of melatonin, which is needed for a good night’s sleep. So if you don’t have adequate amounts of vitamin D, you are more likely to be depressed and sleep poorly.
How much vitamin D is enough? Research suggests it is somewhere around a concentration of 40-60 (ng/dl). Very few people are anywhere near this, because we evolved in a much sunnier environment and we never used to be inside or wear so much clothing as we do now. The only people who have enough vitamin D naturally are those who live in the southern US or closer to the equator and expose large amounts of skin to the midday sun at least 1-2 total hours per week.
If you live north of Atlanta, you cannot make any vitamin D during the winter months no matter how often you expose your skin to the sun.
To achieve a healthy level of vitamin D in the serum, you should take approximately 1,000 units orally per 35 pounds of body weight – and double that if you are obese. That means a normal 175 pound man should be on approximately 5000 units per day. If you are deficient, and take this amount daily for 6 weeks, you should arrive in the healthy range by that time. Vitamin D is very cheap and it can be purchased everywhere.
I take 5000 units per day and my levels are in the 50-60 range. Since I started supplementing a few years ago, I am very rarely ill, even though I am around sick people all the time.
Give it a try, and after 6-12 months, do a look-back and see if you feel better and have been sick less often than before. This time of year is a great time to start since you are likely near your nadir of serum levels.