Data shows the blood’s ability to carry oxygen peaks in late summer, indicating a possible influence by UVB.
Anemia occurs when the body has a low number of red blood cells (RBCs). These cells carry oxygen throughout the body. Fewer RBCs limit the body’s oxygen level.
Risk factors for anemia include:
- Low dietary iron and folate (vitamin B) intake
- Serious illnesses including internal bleeding, kidney disease, cancer, diabetes, HIV/AIDS, and liver disease
- Low vitamin D levels
Sunlight exposure and risk
Dr. John Cannell of the Vitamin D Council presented data on oxygen-carrying capacity of athletes from the mid-1950s. The data showed that the blood’s ability to carry oxygen peaks in late summer, suggesting that UVB during the summer increased RBC count.
Vitamin D and anemia
Vitamin D levels
There are a number of studies linking lower vitamin D levels and higher anemia risk:
- In an Australian study of people with noncholestatic chronic liver disease, lower vitamin D levels were associated with anemia.
- Pregnant women in Tanzania with low vitamin D levels were compared to those with adequate vitamin D levels. The women with low levels had a much higher risk of anemia.
- In the United States, 41% of patients with chronic kidney disease had anemia. Lower vitamin D levels were associated with lower hemoglobin levels and anemia.
- A study in Los Angeles found a link between vitamin D deficiency and anemia.
- A U.S. study compared people with and without anemia. Those with anemia were more likely to have low vitamin D levels.
- Another study reported a direct connection between vitamin D levels and maximum oxygen consumption.
How vitamin D works
It is not known how vitamin D affects red blood cells.
There are no reported studies of vitamin D preventing anemia. However, based on results for other diseases, vitamin D levels above 30–40 ng/mL (75–100 nmol/L) may increase RBCs and oxygen in the blood.
Due to their high iron and vitamin C content, strawberries are beneficial for those with anemia.
According to studies, RBCs rebuild more quickly in people who have higher vitamin D levels. These studies also used iron and other agents to stimulate RBCs. Anyone with anemia should seek medical care.
Find out more…
Do you want to find out more and see the research upon which this summary is based? Read our detailed evidence summary on anemia.
Page last edited: 12 October 2011