Product Review

It is essential to maintain healthy vitamin D levels throughout all stages of life, from fetal development to old age.* Vitamin D helps protect a number of important functions in the body.* The current recommended daily vitamin D intake of 400 IUs is based on the minimum allowance to protect against bone disease. However, an upward revision of the FDA's guideline is now under consideration in light of new research, especially pertaining to immune function. Cutting-edge research suggests serum vitamin D levels should be in the range of 32-80 ng/mL 25-hydroxyvitamin D (25(OH)D). Although direct sunlight exposure is a good source of vitamin D, many people do not get enough sun due to season change, latitude, or lifestyle. Therefore, vitamin D supplementation can be of great benefit in these cases.*

Vitamin D deficiency is quite common, particularly among the elderly.* For example, a study conducted at a hospital in Glasgow, Scotland, found an almost universal vitamin D deficiency among a group of 548 elderly patients. Individuals deficient in vitamin D may need 5,000-10,000 IU of vitamin D daily to replenish tissue stores.* With these individuals specifically in mind, Thorne's D-5,000 supplies 5,000 IU of pure vitamin D3 in each vegetarian capsule.

Some vitamins, because of their potency, are usually given in very small amounts. Examples of such "micro-dose" vitamins include vitamin D, vitamin K, and vitamin B12. Most dietary supplement manufacturers purchase "micro-dose" vitamins from raw material suppliers as premixed dilutions, meaning the vitamins (in powder form) are mixed with other powdered substances that in turn make it easier for the manufacturer to handle and mix a larger quantity of raw material. Unfortunately, the powdered substances used in these premixed dilutions frequently contain potentially detrimental ingredients such as lactose and also the preservatives BHT, BHA, sodium benzoate, and sorbic acid.