– The difference between vitamin D3 and vitamin D2 is that animals can synthesize vitamin D3 whereas plants synthesize vitamin D2.
– When choosing vitamin D supplements, for the optimal result, vitamin D3 is the best choice.
Recommended Vitamin D Intake
There is no doubt about the benefits of vitamin D to our health, but there is still no unified recommendation for how much we should take for the ideal amount. In 2010, the Institute of Medicine (IOM) recommended a daily dose of 600 IU for adults. However, some studies pointed out that this is not enough. A study found that even 2000 IU per day may not be able to maintain normal blood levels. In addition to increasing the recommended intake to 600 IU, the Institute of Medicine also increased the Tolerable Upper Intake Levels (UL) to 4000 IU per day; meanwhile, IOM has also increased NOAEL (No Observed Adverse Effects Level) (the highest consumption without observing toxicity) value to 10,000 IU per day.
In the light of a study by JAMA Internal Medicine, 77% of people in the United States have vitamin D deficiency, which may be more severe in winter. According to a statistical survey conducted by Chi Mei Hospital in Taiwan, more than 60% of Chinese people are vitamin D deficient. Vitamin D supplements on the market can be divided into two main categories, vitamin D2 and vitamin D3, but which vitamin D is more effective?
A study published in the Journal of Clinical Endocrinology & Metabolism in 2011 indicated that for 33 testing subjects, it was found that vitamin D3 performed 87% better than vitamin D2 in increasing vitamin D content in the body (Robert P. Heaney, 2011 ). Vitamin D3 is also more efficient for storing fat cells in the body. Base off of another study published in the European Journal of Clinical Nutrition in 2015 (Beatriz Oliveri, 2015), compared to the testing subjects who take vitamin D2, those who take vitamin D3, even after they stop the supplementation, the effect could remain high for 77 days in their body.
Sources of Vitamin D in Food
Common food sources containing vitamin D3 are egg yolks, beef liver, deep-sea fish rich in fat (such as salmon, sardines).
Common food sources containing vitamin D2 are mushrooms, nutrient-fortified breakfast cereals or milk.
Advice for Vitamin D Supplementation
It is difficult to obtain enough vitamin D from a normal diet. Synthesis through sunlight cannot meet daily needs either, because it is affected by the season, climate, exposure time and specific wavelengths of sunlight. If you want to supplement vitamin D, vitamin D3 is the best choice. It’s recommended 600 IU daily for adults, and the recommendations for children including infants and young children is 400 IU per day. If you are extremely deficient in vitamin D and want to supplement a higher dose, it is recommended to consult a physician, nutritionist or professional first.