Blood type diets lack supporting evidence: a systematic review

Blood Type Is Not Associated with Changes in Cardiometabolic Outcomes in Response to a Plant-Based Dietary Intervention

BACKGROUND

Risk of cardiovascular disease is lower in individuals with blood type O and increased in individuals with blood type A, compared with those in other blood groups. However, little evidence is available regarding whether individuals with different blood types benefit from different diet recommendations.

OBJECTIVE

As part of a larger intervention trial using a low-fat vegan diet, this study ascertained whether changes in cardiometabolic outcomes were associated with ABO blood type.

DESIGN

A secondary analysis among intervention-group participants in a 16-week randomized clinical trial.

PARTICIPANTS/SETTING

In a larger study of overweight individuals randomly assigned to follow a low-fat vegan diet or to make no diet changes for 16 weeks, ABO blood typing was conducted on 68 intervention-group participants.

INTERVENTION

Intervention-group participants were asked to follow a low-fat vegan diet and attend weekly educational classes to aid in diet adherence.

MAIN OUTCOME MEASURES

Body weight, fat mass, visceral fat volume, blood lipid levels, fasting plasma glucose levels, and glycated hemoglobin concentrations.

STATISTICAL ANALYSES PERFORMED

Student t tests compared participants with blood type A to all other participants, and individuals with blood type O to all other participants.

RESULTS

There were no significant differences in any outcome between individuals of blood type A and all other participants, or between individuals of blood type O and all other participants. Mean body weight change was -5.7 kg for blood type A participants and -7.0 kg for all other participants (P = 0.09), and was -7.1 kg for type O participants and -6.2 kg for all other participants (P = 0.33). Mean total cholesterol decreased 17.2 mg/dL in the type A group and 18.3 mg/dL for all other participants (P = 0.90), and decreased 17.4 mg/dL among type O participants and 18.4 mg/dL for all other participants (P = 0.89).

CONCLUSIONS

Blood type was not associated with the effects of a plant-based diet on body weight, body fat, plasma lipid concentrations, or glycemic control.

ABO Genotype Does Not Modify the Association between the "Blood-Type" Diet and Biomarkers of Cardiometabolic Disease in Overweight Adults

Background

Although 7 million copies of Eat Right 4 Your Type have been sold in >60 languages, there has been a lack of evidence supporting the "blood-type" diet hypothesis.

Objective

The present study aimed to examine the validity of this diet in overweight adults.

Methods

A total of 973 adults [mean ± SEM age: 44.6 ± 0.4 y; mean ± SEM body mass index (BMI; kg/m2): 32.5 ± 0.2; 758 women, 215 men] were participants of the Toronto Healthy Diet Study. A 1-mo, 196-item food-frequency questionnaire was used to determine dietary intakes before and after a 6-mo dietary intervention. Diet scores were calculated to determine relative adherence to each of the 4 blood-type diets as a secondary analysis. ABO blood group was determined by genotyping rs8176719 and rs8176746. ANCOVA was used to compare cardiometabolic risk factors across tertiles of diet scores.

Results

At baseline, individuals with a higher adherence score to the type A diet had lower diastolic blood pressure (tertile 3 compared with tertile 1: 70.9 ± 1.1 compared with 73.3 ± 1.1 mm Hg; P < 0.01). Lower waist circumference was observed in individuals with higher adherence to the type B (tertile 3 compared with tertile 1: 100.8 ± 1.8 compared with 105.4 ± 1.7 cm; P < 0.01) and type AB (tertile 3 compared with tertile 1: 101.2 ± 1.8 compared with 104.8 ± 1.7 cm; P < 0.01) diets. After a 6-mo dietary intervention, individuals with increased adherence to the type A and type B diets had greater reductions in BMI and waist circumference, respectively (P < 0.01). Individuals with an increase in type O diet adherence showed decreases in both BMI and waist circumference (P < 0.01). However, matching the diets with the corresponding ABO genotype of each individual did not change the effect size of any of these associations either at baseline or at 6 mo.

Conclusions

ABO genotype does not modify any association between blood-type diets and biomarkers of cardiometabolic disease in overweight adults, suggesting that the theory behind this diet is not valid This study was based on the data of a trial that was registered at www.clinicaltrials.gov as NCT00516620.

Association of ABO Blood Group and Body Mass Index: A Cross-Sectional Study from a Ghanaian Population

ABO blood group and body mass index (BMI) have individually been appraised as risk factors for certain diseases. From statistical perspective, it may be important to examine the relationship between the ABO blood antigen and BMI. This cross-sectional study involved 412 participants aged 18 to 46 at the Kwame Nkrumah University of Science and Technology (KNUST), Kumasi. Weight and height of participants were measured for BMI calculation; blood group determination was done using antisera. Blood group O was the most prevalent (51.2%), while Rhesus-positive individuals constituted 90.3%. 6.3% of the participants were obese, while 18.7% were overweight. There was significant (p=0.006) higher prevalence of obesity in females (10.3%) than in males (3.4%). The study did not observe any significant difference by association of ABO blood group with gender (p=0.973), BMI (p=0.307), or Rhesus status (p=0.723). Regarding gender (p=0.400) and BMI (p=0.197), no statistically significant difference was observed between Rhesus blood groups. The prevalence of overweight, obesity, blood type O, and rhesus positive observed among students in this study is largely similar to what has been reported in published studies in Ghana and from other countries. Overweight and obesity were not associated with ABO blood groups or Rhesus in this study.

Relation between ABO blood groups and obesity in a Saudi Arabian population

Objectives

ABO blood groups have been shown to be associated with different diseases. Very few studies have attempted to detect the association of ABO blood groups with obesity. The goal of this study is to find any potential relation between ABO blood groups and high body mass index (BMI) among a Saudi population, which may contribute to underlying genetic disorders.

Methods

A cross-sectional descriptive study was conducted using a structured questionnaire that contained general demographic data, including weight, height, type of ABO blood group and the participants' opinion, to determine the association between the ABO blood groups and obesity.

Results

Our study included 1171 participants, including 596 (50.9%) women. A plurality of participants' ages (47%) was between 15 and 25 years. The prevalence of obesity was 35.7% in men and 20.3% in women, while the prevalence of overweight was 30% in men and 25.3% in women. Blood group O was reported to be the most common blood group (46%), followed by blood group A (31.4%), while blood groups B and AB were found in 16.1% and 6.5% of participants, respectively. The prevalence of obesity (BMI ≥ 30) among participants based on blood group O, A, B, and AB was 13.7%, 9%, 4.8%, and 2.2%, respectively. There was no statistically significant difference between the prevalence of obesity or high BMI and ABO blood groups.

Conclusion

Overall, our study did not show a significant relation between overweight and obesity and ABO blood groups. However, the elevation of the prevalence of overweight and obesity, mainly among the younger generations of the Saudi population, requires more awareness and educational programs.

Nutrigenomics, the Microbiome, and Gene-Environment Interactions: New Directions in Cardiovascular Disease Research, Prevention, and Treatment: A Scientific Statement From the American Heart Association

Cardiometabolic diseases are the leading cause of death worldwide and are strongly linked to both genetic and nutritional factors. The field of nutrigenomics encompasses multiple approaches aimed at understanding the effects of diet on health or disease development, including nutrigenetic studies investigating the relationship between genetic variants and diet in modulating cardiometabolic risk, as well as the effects of dietary components on multiple "omic" measures, including transcriptomics, metabolomics, proteomics, lipidomics, epigenetic modifications, and the microbiome. Here, we describe the current state of the field of nutrigenomics with respect to cardiometabolic disease research and outline a direction for the integration of multiple omics techniques in future nutrigenomic studies aimed at understanding mechanisms and developing new therapeutic options for cardiometabolic disease treatment and prevention.

ABO genotype, 'blood-type' diet and cardiometabolic risk factors

BACKGROUND

The 'Blood-Type' diet advises individuals to eat according to their ABO blood group to improve their health and decrease risk of chronic diseases such as cardiovascular disease. However, the association between blood type-based dietary patterns and health outcomes has not been examined. The objective of this study was to determine the association between 'blood-type' diets and biomarkers of cardiometabolic health and whether an individual's ABO genotype modifies any associations.

METHODS

Subjects (n = 1,455) were participants of the Toronto Nutrigenomics and Health study. Dietary intake was assessed using a one-month, 196-item food frequency questionnaire and a diet score was calculated to determine relative adherence to each of the four 'Blood-Type' diets. ABO blood group was determined by genotyping rs8176719 and rs8176746 in the ABO gene. ANCOVA, with age, sex, ethnicity, and energy intake as covariates, was used to compare cardiometabolic biomarkers across tertiles of each 'Blood-Type' diet score.

RESULTS

Adherence to the Type-A diet was associated with lower BMI, waist circumference, blood pressure, serum cholesterol, triglycerides, insulin, HOMA-IR and HOMA-Beta (P<0.05). Adherence to the Type-AB diet was also associated with lower levels of these biomarkers (P<0.05), except for BMI and waist circumference. Adherence to the Type-O diet was associated with lower triglycerides (P<0.0001). Matching the 'Blood-Type' diets with the corresponding blood group did not change the effect size of any of these associations. No significant association was found for the Type-B diet.

CONCLUSIONS

Adherence to certain 'Blood-Type' diets is associated with favorable effects on some cardiometabolic risk factors, but these associations were independent of an individual's ABO genotype, so the findings do not support the 'Blood-Type' diet hypothesis.