The Institute of Medicine (IOM) review panel noted that although most people do
not need extra vitamin D, several populations are potentially at risk of vitamin D
deficiency and may require extra vitamin D in the form of supplements or fortified
foods. They include:

• Exclusively breastfed infants: Human milk only provides 25 IU of vitamin D
per liter. On the advice of a medical professional, nearly all breastfed and
partially breastfed infants will be recommended to be given a vitamin D
supplement of 400 IU/day.
• Dark skin: Those with dark pigmented skin synthesize less vitamin D upon
exposure to sunlight compared to those with light pigmented skin.
• Elderly: This population has a reduced ability to synthesize vitamin D upon
exposure to sunlight, and is also more likely to stay indoors and wear sunscreen
that blocks vitamin D synthesis.
• Covered and protected skin: Those who cover all of their skin with clothing
while outside, and those who wear sunscreen with an SPF factor of 8 or
higher, block most of the synthesis of vitamin D from sunlight.
• Disease: Fat malabsorption syndromes, inflammatory bowel disease (IBD), and
obesity are all known to result in a decreased ability to absorb and/or use
vitamin D in fat stores.

In all of these circumstances, it is a good idea to get a blood test to see if the serum
25-hydroxyvitamin D (25(OH)D) level is substantially less than the IOM recommended average of 20 ng/ml (50 nmol/liter).
In an article titled Vitamin D Deficiency—Is There Really a Pandemic? In the New England Journal of Medicine, Manson
and her colleagues caution that many people will have a requirement of only16 ng
or even less, and that ensuring that 97.5% of the population attain or exceed 25(OH)
D levels of 20 ng per milliliter would requiring shifting the entire population to a
higher intake and harm people whose intake is pushed above the Tolerable Upper
Intake Level of 4000 IU per day. The authors suggest that almost all of those who
are potentially at risk (as described above) will have adequate vitamin D with supplementation
of the Recommended Daily Allowance (RDA) of 600 to 800 IU per day, as is recommended by the Institute of Medicine.

This blog presents opinions and ideas and is intended to provide helpful general information. I am not engaged in rendering advice or services to the individual reader. The ideas, procedures and suggestions in that are presented are not in any way a substitute for the advice and care of the reader’s own physician or other medical professional based on the reader’s own individual conditions, symptoms or concerns. If the reader needs personal medical, health, dietary, exercise or other assistance or advice the reader should consult a physician and/or other qualified health professionals. The author specifically disclaims all responsibility for any injury, damage or loss that the reader may incur as a direct or indirect consequence of following any directions or suggestions given in this blog or participating in any programs described in this blog or in the book, The Building Blocks of Health––How to Optimize Your Health with a Lifestyle Checklist (available in print or downloaded at Amazon, Apple, Barnes and Noble and elsewhere). Copyright 2021 by J. Joseph Speidel