JAND: Does blood type affect the benefits of a healthy diet?

A recent study published in Journal of the Academy of Nutrition and Dietetics by researchers at Physicalians Committee for Responsible Medicine, a non-profit group of 12,000 doctors, found that blood type differences do not affect the effects of healthy eating on the body, such as weight, body fat, plasma lipid concentration, or blood sugar control.
blood type study is part of a larger study on the metabolic effects of a low-fat vegetarian diet using a single-center, randomized, open parallel design between January 2017 and December 2018.
researchers recruited adult men and women with a body mass index (BMI) between 28 and 40 in the Metropolitan Area of Washington, D.C.
exclusion criteria include a history of diabetes, alcohol or drug use, pregnancy, breastfeeding or current vegan use.
results were published in JAMA Network Open on November 30.
244 participants who met the criteria in the trial were randomly assigned to the intervention or control group with a 1:1 ratio of overweight participants with no history of diabetes for 16 weeks.
randomized clinical trial flowcharts of the effects of blood type on plant-based dietary interventions on health outcomes The intervention group was asked to avoid animal products, while focusing on fruits, vegetables, grains and legumes, and to limit the addition of oil and nuts.
daily dietary fat intake is limited to 20 to 30 g, vitamin B-12 (500 mg/day).
control group were asked to maintain their current diet, which included animal products, during the study period.
who were assigned to a vegetarian group were instructed to attend weekly classes, provide dietary guidance and encourage adherence to diet.
by research physicians, registered dietitians, and researchers in person in accordance with the established curriculum.
to consider the potential link between blood type and diet, the researchers took additional steps to conduct a secondary analysis of participants in the intervention group in the 16-week randomized clinical trial.
they considered whether the effects of plant-based dietary interventions on weight, lipids and blood sugar control were related to ABO blood type.
"blood type diet" recommends a plant-based diet for people with type A blood, while a meat-based diet is recommended for people with type O blood.
results showed that there was no significant difference between blood groups in baseline average weight, BMI, fat mass, visceral fat volume and HbA1c concentration.
average total cholesterol and LDL cholesterol levels were in type A blood (226.5 mg/dL and 138.9 mg/dL) and non-A blood (184.2 mg/dL and 107.6 mg/dL) significantly increased between type O blood (182.4 mg/dL and 105.0 mg/dL) and non-O blood (208.6 mg/dL and 126.5 mg/dL, respectively).
dietary changes, especially increased intake of fruits, vegetables and cereals, are beneficial not only to individuals with type A blood, but also to all individuals.
regardless of blood type, there is no obvious value in limiting these healthy dietary changes to a specific group of individuals based on ABO blood type.
study has several advantages.
all participants in each queue at the same time, allowing respondents to rule out the possible effects of seasonal fluctuations in their diet.
study lasted a long time and provided enough time to adapt to the diet.
low rate of loss indicates that interventions are acceptable and sustainable, providing a reasonable test of hypothesis.
take into account that participants live at home, cook their own meals or eat in restaurants, these results apply to free living conditions.
study also has limitations.
of individuals with TYPE AB and type B blood is lower.
improved statistical power by combining blood types (A and non-A, O and non-O).
dietary intake is based on self-reported dietary records, which have well-known limitations.
, however, it is gratifying that the reported changes in nutrient intake are parallel to changes in weight loss and metabolism.
are generally health-conscious people who are willing to make substantial changes to their diet.
, they may not represent the general population, but they may represent clinical populations seeking help with weight problems.
: 1.New study debunks blood type diet 2.Neal D. Barnard et al, Blood Is Is Not Associated with Changes in Cardiometabolic Outcomes in Response to a Plant-Based Dietary Intervention, Journal of The Academy of Nutrition and Dietetics (2020). DOI: 10.1016/j.jand.2020.08.079。