Menu Close

Vitamin D- Nutrition Series by Caroline Devine

Submitted by Carolyn Devin of Serenity of Body and Mind, CT, USA
The fourth in a series of talks about the importance of vitamins.


Hello everyone! This is the fourth part of my vitamin blog series and today I will be talking about Vitamin D.  Vitamin D is also called the sunshine vitamin but it isn’t actually a “vitamin” at all.  It is actually more accurately described as hormone-like.  When the skin is exposed to adequate UV light it can synthesize vitamin D from a type of cholesterol in the skin.  Many, many people in the United States, especially in the northern states, are deficient in this vitamin.

The best natural food sources of vitamin D are fatty fish such as sardines and salmon.  Cod liver oil was very popular in the 1930s as a supplement because of its high vitamin D content.  Two tablespoons of cod liver oil provide 680% of the daily recommended amount of vitamin D.  Three ounces of tuna provides about 50% and three ounces of salmon is about 150%.  Milk provides the bulk of the United States recommended amount as it is heavily fortified with vitamin D which helps with the processing of calcium.

For Connecticut people to get vitamin D from the sun we would need to be in the sun, unprotected (meaning without any sunblock), for 20 minutes, 4-5 times per week, and it would have to be between the months of March and October.  The rest of the year the sun is not strong enough to produce the vitamin D in the skin so we should be supplementing.  The problem is that many people don’t go in the sun in the summer or are entirely covered in sunblock.  Now I don’t recommend that people should be out in the sun for hours at a time with no sun protection but for a little while every other day will definitely be a health benefit.  And get tested for deficiency by your doctor so you’ll know what your vitamin D status is.

The function of vitamin D in the body is very similar to hormonal regulation.  Vitamin D regulates the body’s concentration of calcium and phosphorus which is extremely important for bone health and maintaining the pH of the blood.  In this society there is a lot of emphasis on calcium and bones but without vitamin D, calcium doesn’t really work as it should.  Calcium and vitamin D go hand in hand which is why milk is a good food for vitamin D fortification.

Vitamin D has also been found to be important in immune functions and cellular metabolism.  Adequate levels of vitamin D can help prevent infection and there are studies that show vitamin D can actually decrease the likelihood of certain diseases such as multiple sclerosis, hypertension, and possibly certain cancers.

Severe vitamin D deficiency in children causes rickets.  When children are growing and developing, calcium and phosphorus are very important to the mineralization of the bones.  When vitamin D levels are low the body cannot regulate the calcium and phosphorus which causes the bones to be weak and brittle.  A common trait of children with rickets is bowed legs, deformed pelvises, and enlarged heads.  Vitamin D deficiency in adults is called osteomalacia and is translated to “soft bones”.  This results in fractures of the hips, spine, and other bones.  This is not the same as osteoporosis as it has more to do with mal-absorption of vitamin D and calcium whereas osteoporosis is actual loss of bone mass.

Vitamin D toxicity can occur with too much supplementation.  It cannot occur with too much sun exposure as the body will self-regulate the amount of vitamin D it will produce.  Excess vitamin D can cause increased calcium in the blood which leads to calcium deposits in the kidneys, heart, and lungs.  Other symptoms are nausea, weakness, joint pain, and disorientation.  In early stages this can be treatable but continued excess supplementation can be fatal.