If you’re lactose intolerant, you probably know to avoid milk or pay the price with cramps, wind, or diarrhoea. What you may be unaware of, however, is that avoiding milk and dairy products might put you at risk of low vitamin D levels, according to a study published in the Journal of Nutrition. For the study, researchers took blood samples from 1,495 men and women, ages 20 to 29, who participated in the Toronto Nutrigenomics and Health Study. Using genetic testing, they identified participants with variants of a gene, known as the LCT gene, associated with lactose intolerance. They also assessed participants’ vitamin D status by measuring blood 25(OH)D levels, and checked dairy intake via food frequency questionnaires. They found that:

• Participants with the lactose intolerance-associated LCT gene variants consumed less total dairy and less skimmed milk than those without these LCT gene variants.
• The risk of having sub-optimal blood vitamin D levels was between 50 and 200% higher in participants with these LCT gene variants than in those without these LCT gene variants.

While these findings don’t directly connect low dairy intake with low vitamin D, they do suggest that people with a low intake of dairy foods may need to find other ways to maintain a healthy vitamin D status. It is important to note that ethnic groups with the highest prevalence of lactose intolerance—people of African, Asian, and South, Central, and North American Native descent—also have darker skin pigmentation, which can be a major factor in low vitamin D status. Until we know more about the relationship between dairy intake and vitamin D status, people who are lactose intolerant may benefit from eating non-dairy sources of vitamin D such as salmon and tinned tuna, cod liver oil, and vitamin D-fortified foods such as cereal and orange juice. A vitamin D supplement may also be a wise choice, but talk with your doctor before adding any new supplements to your regimen.

Source: Journal of Nutrition