Posted on May 18, 2017, 6 a.m.
Research reveals that people genetically intolerant to lactose have lower blood levels of vitamin D than the general population.
Researchers at the University of Toronto have determined individuals who are genetically intolerant to lactose have comparably lower levels of vitamin D than the rest of the population. Lactose is the primary sugar in dairy products.
About the Study
Ahmed El-Sohemy, a University of Toronto professor of nutrition within the Faculty of Medicine department authored the study along with Ohood Alharbi. Alharbi is a PhD candidate at the University of Toronto's department of nutritional science. The study examined nearly 1,500 Canadian men and women of varying ethnicities. Lactose intolerance was found across people in all ethnic groups. However, the largest percentage of lactose intolerant individuals is amongst those with East Asian heritage. Study details will be published in an upcoming edition of Journal of Nutrition.
A Closer Look at the Findings
The research team determined those with a gene linked to lactose intolerance ate less dairy products than individuals who lacked the variation of the gene. This gene is referred to as "LCT". Lactose intolerant individuals also had comparably low levels of vitamin D in their blood. This should not come as a major surprise as most dairy products are fortified with the vitamin. The vast majority of people do not get enough of the vitamin from other nutritional sources or through exposure to the sun. Therefore, dairy products are fortified with the vitamin in an effort to boost health.
The research team was not surprised that lactose intolerant individuals consumed less dairy. However, they were surprised that these individuals failed to compensate by supplementing or eating other foods fortified with vitamin D.
Why the Findings are Important
The study results make the case to heighten awareness amongst those who limit their dairy consumption due to lactose intolerance. These individuals must be proactive in their push to obtain ample vitamin D from fortified foods such as select brands of orange juice. These individuals can also obtain vitamin D from dairy products that do not contain lactose.
The research team confirmed prior findings that individuals who have the gene that causes lactose intolerance are shorter than those who lack the gene. This confirmation indicates insufficient intake of this vital nutrient hinders bone growth. The researchers also found that individuals with one (as opposed to two) copies of the variant were impacted by lactose intolerance. However, they were affected to a lesser degree. This finding suggests genetic classifications and clinical definitions of lactose intolerance can be widened.
Ohood Alharbi et al. Lactose Intolerance (-13910C>T) Genotype Is Associated with Plasma 25-Hydroxyvitamin D Concentrations in Caucasians: A Mendelian Randomization Study, The Journal of Nutrition (2017). DOI: 10.3945/jn.116.246108