Vitamin D Testing

Vitamin D is crucial for our overall health and well-being. It plays a vital role in calcium absorption, which is essential for strong bones and teeth12.

Additionally, vitamin D supports our immune system, muscles, brain function, and helps regulate blood pressure6.

Generation and Absorption

The human body can produce vitamin D when our skin is exposed to sunlight, specifically UVB rays23. This process occurs in the skin, where a compound called 7-dehydrocholesterol is converted into vitamin D3 through a series of chemical reactions27. However, factors like skin tone, age, and sun exposure can affect this natural production3.

Best Ways to Obtain Vitamin D

1. Sunlight exposure: Spending time outdoors is an effective way to boost vitamin D levels. However, the amount needed varies based on factors like skin tone and time of day3.

2. Diet: Consuming vitamin D-rich foods can help maintain adequate levels4.

3. Supplements: In some cases, vitamin D supplements may be necessary, especially for those with limited sun exposure or dietary restrictions1.

Absorption

Vitamin D is fat-soluble, meaning it's best absorbed when consumed with fatty foods8. When taken orally, it reaches maximum levels in the blood after about 24 hours8.

Recommended Daily Allowances RDA (often referred to by health practitioners as the Ridiculous Daily Allowance as the amounts are so so low and insufficient for most people)

I, and many others, take 10,000 IU daily.

The general recommended daily allowance (RDA) for vitamin D is 600-800 IU per day for most adults1. However, specific recommendations may vary:

• Children: 400-600 IU per day

• Adults up to 70 years: 600 IU per day

• Adults over 70 years: 800 IU per day

• Pregnant and breastfeeding women: 600 IU per day

For people with vitamin D deficiency or certain health conditions, higher doses may be recommended under medical supervision1.

Food Sources and Other Sources

1. Fatty fish (salmon, herring, sardines)49

2. Cod liver oil9

3. Egg yolks4

4. Mushrooms (especially those exposed to UV light)4

5. Fortified foods (milk, orange juice, cereals)9

6. Sunlight exposure23

7. Supplements (when necessary)1

To optimise absorption, consume vitamin D-rich foods with a source of healthy fats, and consider taking supplements with meals if recommended by a healthcare provider8.

Citations:

1. https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/
2. https://en.wikipedia.org/wiki/Vitamin_D
3. https://www.healthline.com/nutrition/how-to-increase-vitamin-d
4. https://www.medicalnewstoday.com/articles/324590
5. https://www.betterhealth.vic.gov.au/health/healthyliving/vitamin-d
6. https://www.healthdirect.gov.au/vitamin-d-and-your-health
7. https://en.wikipedia.org/wiki/Cholecalciferol
8. https://pmc.ncbi.nlm.nih.gov/articles/PMC7731935/
9. https://www.healthline.com/nutrition/9-foods-high-in-vitamin-d
10. https://longevity.stanford.edu/lifestyle/2024/03/11/vitamin-d-benefits-sources-deficiency/
11. https://www.yalemedicine.org/news/vitamin-d-myths-debunked
12. https://www.medicalnewstoday.com/articles/161618
13. https://nutritionsource.hsph.harvard.edu/vitamin-d/
14. https://www.healthline.com/health/food-nutrition/benefits-vitamin-d