The health benefits of Vitamin D are not well understood by most people, many thinking it being needed only to prevent rickets which they believe to be no longer a disease of the 21st century. There is a great deal of misinformation about Vitamin D, and a need for education in what it is and why it is essential to your health.
The following are the aspects of Vitamin D that are either misunderstood, or about which the vast majority people have very little understanding:
- The health benefits of Vitamin D
- How much sunlight is needed to produce your daily requirement
- How your clothing and where you live affects your need for a Vitamin D supplement
- Vitamin D and your diet
- When you need a supplement, and in what form it should be taken
The Health Benefits of Vitamin D
1. Rickets and Bone Disease
Most educated people know that a lack of Vitamin D causes rickets, without really understanding how much constitutes ‘a lack’ or what rickets is, other than it is a disease of the bones. The truth is that Vitamin D helps regulate the relative amounts of blood calcium and phosphorus, and also of the absorption of these minerals into your bones. Both calcium and phosphorus are essential for healthy bones.
If young children are short of Vitamin D their bones fail to develop properly, and become weak and malformed. This is rickets. In adults a similar condition is known as osteomalacia, and a deficiency can lead to osteoporosis and also muscular problems.
Most people believe rickets to be a disease of the past, but they are wrong on two counts.[1] First, it is not a disease but a condition of young children caused by a deficiency of Vitamin D, either in their diet or through a lack of exposure to sunlight. Secondly, it is still in existence, and even in the UK and the USA cases of rickets are increasing as children spend less time playing outdoors.
People subject to certain illnesses or conditions can also suffer a Vitamin D deficiency. Cystic fibrosis, Crohn’s disease, obesity and even old age can result in a deficiency that can lead to problems with bone structure.
2. Blood Pressure
All the available evidence points to Vitamin D helping to lower blood pressure, or reduce hypertension [2]. Many studies have shown hypertension to vary by season, being highest during periods when sunlight is low. It has been suggested that Vitamin D helps to direct calcium in the blood to the bones and so prevent it being incorporated in the arteries [3]. This hardens them, rendering them less flexible and so increases blood pressure.
This vitamin is also believed to increase insulin sensitivity, a known risk factor for high blood pressure. Several tests carried out on supplementation have indicated that a supplement helps reduce blood pressure, even in those with chronic hypertension.
3. Infections
There is documented evidence that one of the benefits of Vitamin D is reducing the likelihood of certain infections. For example, those with an adequate intake of the vitamin are less liable to suffer or even die from influenza. Trials carried out in both the USA and Japan [4] have confirmed this.
It has also been established that those with a Vitamin D deficiency are more liable to have MRSA bacteria in their nasal passages. Other Vitamin D benefits for which there is yet no prima facie case include resistance to HIV/AIDS, to meningitis and to dietary anaphylactic shock. There are theoretical reasons and reported cases for these benefits, but they have yet to be proven using controlled human trials.
How Much Sunlight is Needed?
Exposure to the Ultraviolet B (UVB) light in the sun’s rays generates a natural form of Vitamin D known as Cholecalciferol (D3). Your body is designed specifically to produce this form of the vitamin through exposure to rays of the UVB wavelength band. The angle of the sun’s rays is very important, and during winter and the early and later hours of the day, the rays are at too sharp and angle and are largely absorbed by the atmosphere – if your shadow in full sunlight is shorter than you are, then you are OK. Otherwise you are not generating enough Cholecalciferol to keep you healthy.
For example, at noon in Boston an average white-skinned person will need one hour of 40% body exposure for their daily needs, while only 6 minutes in Miami. The darker your skin, the longer you need. It is obvious that outside mid-summer most people need a supplement [5].
Effect of Your Clothing
The less clothing you wear, the less of a supplement you will need. You will receive all your needs of Cholecalciferol when expose 40% of your body for up to an hour (or equivalent – 20% for 2 hours and so on), depending on your locality. However, if you are fully clothed from head to toe, you will receive next to no Cholecalciferol, and will therefore need a supplement.
Devout Muslim women will rarely receive sufficient Vitamin D, particularly those living in temperate climates or those with low levels of strong sunlight. The same is true of children that spend most of their day indoors with their computer or people who work indoors all day, and enjoy the sun only at weekends. Prisoners without sufficient daylight exposure will also suffer.
Vitamin D in Your Diet
If you must take a supplement to enjoy the full benefits of Vitamin D, the foods highest in this vitamin do not include sufficient to be of much benefit to you. In fact, your dietary intake of this vitamin is very low, irrespective of the claims made by food producers. It is present in large quantities in cod liver oil, but how many of us eat cod livers as a daily foodstuff? If you require a supplement, you will not get it by changing your diet.
Getting the Benefits of Vitamin D from Supplements
The two supplements of most benefit are cod liver oil and a lanolin-based dry powder. Lanolin is an oil obtained from lamb’s wool that can be dried to a powder. Each of these is available in capsule form and should be taken according to the instructions on the label.
So-called vegetarian Vitamin D is the D2 variety, Ergocalciferol, not considered a sufficient good alternative to the natural D3, or Cholecalciferol. [5] Those that cannot take the cod liver oil or lanolin supplements must make sure they get sufficient sun exposure in order to avoid the problems associated with a deficiency.
However, the D2 variety is likely better than no supplement at all and recommendations can be found here: Food and Nutrition Board Dietary Supplement Fact Sheet: Vitamin D.
These are the facts about the health benefits of Vitamin D. It is now up to you to use them to your benefit.
References:
1. Pettifor, J. M. Vitamin D &/or calcium deficiency rickets in infants & children: a global perspective. Indian J Med Res. 2008 Mar; 127 (3): 245-9.
2. http://www.vitamindcouncil.org/health-conditions/cardiovascular-diseases/hypertension/
3. Pilz, S. Tomaschitz, A. Role of vitamin D in arterial hypertension. Expert Rev Cardiovasc Ther. 2010 Nov; 8 (11): 1599-608.
4. Urashima, M. Segawa, T. Okazaki, M. Kurihara, M. Wada, Y. Ida, H. Randomized trial of vitamin D supplementation to prevent seasonal influenza A in schoolchildren. Am J Clin Nutr. 2010 May; 91 (5): 1255-60.
5. Houghton L.A., Vieth R. The case against ergocalciferol (vitamin D2) as a vitamin supplement. Am J Clin Nutr. 2006 Oct; 84 (4): 694-7.
