Supporters of the diet claim that some blood types are more at risk for diabetes than others due to genetic factors relating to blood types. They also claim that certain blood types should avoid specific foods that are not suitable for them. These foods can increase their blood sugar, cholesterol, and triglyceride levels, increasing their risk of diabetes.
On the other hand, opponents of the diet claim that there’s no scientific evidence to support the blood type diet hypothesis. Research has found that there is no link between the blood type diet and improved diabetes. Thus, the diet does not affect an individual’s diabetes prognosis.
Opponents of the diet believe that the blood type diet might improve a person’s health, but this is because it encourages people to follow a healthy lifestyle and exercise regularly. Accordingly, it has nothing to do with certain blood types eating specific foods since all of the blood types metabolize foods in the same way.
Opinion in favor of following the blood type diet for diabetes:
Peter D’Adamo, the creator of the blood type diet, claims that there is a link between blood type and diseases like diabetes. According to him, all blood types can develop diabetes if they cannot produce enough insulin to lower their blood sugar levels. However, each blood type is predisposed to develop diabetes if they eat harmful lectins that impair the body’s utilization of food and insulin, and cause weight gain.
For instance, blood type A and AB individuals have an increased risk of diabetes because they secrete high levels of cortisol in their blood. They also cannot metabolize fats as well as other blood types.
Both high levels of cortisol and high levels of fat in the bloodstream may cause type A and AB individuals to have higher blood sugar levels compared to other blood types. However, they can regulate their blood sugar and fat level by avoiding high fat and high protein food that they cannot digest.
Meanwhile, blood type O and B individuals can be at risk for diabetes because they cannot digest carbohydrates efficiently. If they avoid foods with harmful lectins that impair their metabolism and insulin function, they may decrease their risk of diabetes.
Research shows that some lectins interfere with insulin function. For instance, in 2017, a study titled, “Plant Lectins Activate the NLRP3 Inflammasome To Promote Inflammatory Disorders” found that some plant lectins stimulate an inflammatory response that may affect a person’s risk for developing diabetes. However, the study concludes that everyone is equally affected by inflammation caused by plant lectins. In contrast, the blood type diet claims that different lectins affect each blood type differently.
In addition, D’Adamo claims that blood types that are more likely to be overweight or obese have a higher risk of developing diabetes. D’Adamo claims that obesity “produces leptin resistance and it promotes insulin resistance,” insisting that leptin production can cause insulin resistance.
In 2016, a study titled the “Relationship between serum leptin and insulin resistance among obese Nigerian women” examined the link between leptin and insulin resistance among women in Nigeria. It found a strong link between leptin and insulin resistance. However, it could not demonstrate that leptin is a “predictive factor” for insulin resistance due to the study’s small sample size. Further studies need to be done to determine at what levels leptin can cause insulin resistance.
Opinion against following the blood type diet for diabetes:
Many medical experts believe that there is a link between an individual’s blood type and diabetes. However, there is insufficient scientific evidence to support the hypothesis that the blood type diet, or eating particular foods according to our blood type, has any effect on an individual with diabetes.
Opponents of the blood type diet believe that the diet may help manage diabetes because it encourages healthy eating habits, such as eating organic fruits and vegetables, not because it provides the proper food for each blood type.
Therefore, regardless of the blood type, if any person eats processed meats, high sugar foods, and refined carbohydrates, that person’s blood sugar levels may increase. The individual’s insulin function may also be impaired. So, when people stop consuming these foods, they can regulate their blood sugar levels and lower their risk of developing diabetes.
As such, the blood type diet is not specific to one blood type as D’Adamo claims. Rather, it affects people of all blood types in the same way.
Furthermore, the diet’s opponents dispute D’Adamo’s claim that obesity and diabetes are linked. They agree that obesity is one of the risk factors of diabetes but disagree on whether obesity leads to insulin as well as leptin resistance.
In the 2017 study, “A Review of the Leptin Hormone and the Association with Obesity and Diabetes Mellitus,” Facey et al. agree that while leptin is “strongly associated” with obesity and diabetes, it does not directly cause diabetes. In fact, they argue that the causes of leptin resistance are “unclear” and that more research is needed to identify the mechanisms behind it. They also mention that leptins can be used to treat diabetes.
In fact, recently, research is exploring whether leptin can be used to treat diabetes. A 2012 study, “The Potential of Leptin for Treating Diabetes and Its Mechanism of Action,” found that leptin therapy was able to treat and even reverse diabetes in animals. The introduction of leptin also helped reduce insulin resistance.
Healthcare professionals also believe that the blood type diet might not be suitable for some people with diabetes. For example, blood type O individuals are encouraged to include more red meat in their diet. However, consuming more red meat might increase the risk of diabetes because red meats have higher levels of saturated fats than other sources of protein.
Saturated fats elevate the body’s insulin levels and worsen metabolism. These two factors may be precursors to developing diabetes. Thus, some foods prescribed to specific blood types may put them at risk for diabetes.
Furthermore, although studies are exploring the effect of the blood type diet on different diseases, the impact of the blood type diet on diabetes is understudied. Experts need to conduct more research to examine whether the blood type diet can prevent or treat diabetes based on different blood types as the theory behind the diet suggests.