Latest Insights on Vitamin D

Vitamin D is one of the most common vitamins and supplements taken by people. It is also a supplement about which a lot has been written and published in allopathic medicine and homoeopathy literature. In a US survey done in 2020 66% of respondents reported that they purchased vitamin D supplements.  Although Vitamin D is not a true vitamin (defined as a nutrient that cannot be endogenously synthesised), as intake is not required in those who have adequate sun exposure, yet it is considered an important supplement for bone health and to boost the immune system.  It can be found in fatty fish, egg yolks, beef liver, mushrooms, and fortified foods like milk, orange juice, cereal, soy milk, and yogurt.

The last Endocrine Society guidelines were published in 2011 and based on that labelled vitamin D status as “deficient” when serum hydroxyvitamin D (25[OH]D) was lower than 20 ng/mL, and “insufficient” when serum 25(OH)D was 20 ng/mL to 29 ng/mL. Now, the Society “no longer endorses specific 25(OH)D levels to define vitamin D sufficiency, insufficiency, and deficiency.

” In its recent publication The Journal of Clinical Endocrinology & Metabolism, Volume 109, Issue 8, August 2024, Endocrine Society recommends new guidance for how much vitamin D healthy people with no underlying conditions should receive daily. For most people, the guideline recommends following the National Academy of Medicine’s recommended daily empiric vitamin D allowance.

The National Academy of Medicine states that adults aged 19 to 70 years should receive 600 IU daily vitamin D increasing to 800 IU for adults older than 70 years. That recommended level includes vitamin D intake from dietary and supplemental sources.

1. Children and Adolescents (Ages 1-18):
   • Recommendation: The Endocrine Society suggests giving vitamin D supplements to children and teenagers to prevent nutritional rickets, a condition caused by vitamin D deficiency that leads to soft and weak bones. Additionally, the supplement may help reduce the risk of respiratory tract infections.
   • Why it matters: Children and adolescents are in critical stages of bone growth and development. Without sufficient vitamin D, they are at risk of bone deformities and other health problems.
2. Non-pregnant Adults Under 50 Years:
   • Recommendation: For adults under 50, the Society recommends against routine vitamin D supplementation if they don’t have any underlying conditions. Similarly, they advise against routine testing of vitamin D levels.
   • Why it matters: For healthy adults under 50 who get enough sunlight and have a balanced diet, vitamin D deficiency is less common, and supplementation or regular testing isn’t
   • generally necessary unless there are specific risk factors like low sun exposure or poor diet.
3. Adults Aged 50-74 Years:
   • Recommendation: The Society suggests not routinely using vitamin D supplements or testing vitamin D levels for adults in this age group unless they have known risk factors or symptoms of deficiency.
   • Why it matters: While bone health becomes a concern as people age, especially in postmenopausal women, routine supplementation isn't recommended unless there is an identified need based on clinical assessments.
4. Adults Aged 75 Years and Older:
   • Recommendation: For adults over 75, vitamin D supplements are recommended because of their potential to reduce the risk of mortality (death) by strengthening bones and possibly improving overall health. However, routine testing of vitamin D levels is not suggested.
   • Why it matters: Older adults are at higher risk for fractures, falls, and bone weakness due to decreased vitamin D levels. Supplementing vitamin D can help support bone health and longevity. Testing, however, isn’t necessary unless there’s a specific concern.
5. During Pregnancy:
   • Recommendation: Pregnant women should consider vitamin D supplementation due to its potential to reduce the risk of complications such as preeclampsia (a pregnancy condition marked by high blood pressure), intra-uterine mortality (fetal death), preterm birth, and small-for-gestational-age birth. Routine testing for vitamin D levels during pregnancy is not recommended unless the woman is at risk for deficiency.
   • Why it matters: Vitamin D is important for the development of the baby and the health of the mother. Low vitamin D levels in pregnancy can lead to complications, but regular testing isn’t needed unless there are risk factors like darker skin, limited sun exposure, or a vegetarian diet.
6. Adults with Prediabetes:
   • Recommendation: In adults with high-risk prediabetes, vitamin D supplements, in addition to lifestyle changes like diet and exercise, are suggested to reduce the risk of progressing to type 2 diabetes.
   • Why it matters: Prediabetes is a warning sign of developing diabetes, and vitamin D may help regulate blood sugar levels, potentially lowering the risk of the condition worsening.
7. Vitamin D Dosing:
   • Recommendation: For adults aged 50 years and older who need vitamin D supplementation, the Society recommends daily, lower-dose vitamin D rather than taking larger doses less frequently (like weekly or monthly).
   • Why it matters: Daily supplementation ensures a more consistent level of vitamin D in the body, which may be more effective for bone health and overall well-being in older adults.
8. Routine Vitamin D Screening for Healthy Adults:
   • Recommendation: The Society suggests against routine screening for vitamin D levels in healthy adults, including those with dark skin (who might be at greater risk of deficiency due to lower vitamin D production from sunlight) and those with obesity (which can affect vitamin D metabolism).
   • Why it matters: Routine testing isn’t necessary in most healthy people unless there’s a specific reason, such as symptoms of deficiency or high-risk factors like limited sun exposure or other health conditions.

Key takeaway: While vitamin D is essential for health, especially for bones and the immune system, the Endocrine Society suggests that routine supplementation and testing are not necessary for everyone. It should be based on specific risk factors, health conditions, and individual needs. Always consult your doctor before starting vitamin D supplements.

By: Dr Tasaduq Hussain Mir

Author specialises in Family Medicine and is based in USA