By Katharine Lang — Fact checked by Alexandra Sanfins, Ph.D.
According to the CDC, more than 37 million adults in the United States have diabetes, and of these, around 95% have type 2 diabetes. Type 2 diabetes (T2D) develops when a person’s body stops responding to the insulin (the hormone that regulates blood glucose levels) produced by cells in their pancreas.
In contrast, people with type 1 diabetes, which is thought to be caused by an autoimmune reaction, do not produce insulin. They must test their blood glucose level regularly and use insulin to keep it within a healthy range.
A recent study has suggested that a low carbohydrate diet may decrease T2D risk. However, this study was unable to differentiate whether this finding was entirely due to reduction in carbohydrate or just calorie reduction.
Dr. Eamon Laird, visiting research fellow at Trinity College Dublin in Ireland, who was not involved in the study, told Medical News Today: “It’s a very complex topic. We know already that consuming whole grains and plant-based foods is good for diabetes risk reduction.”
Now, a study, which has yet to be published in a peer-reviewed journal, has suggested that it is not the low-carbohydrate diet but the type of non-carbohydrate food that a person eats that affects the risk of developing T2D.
Risk factors for diabetes
T2D usually develops slowly and can have few symptoms at first, so may go unnoticed for some time. A person’s risk of developing T2D is increased by factors such as:
- being over the age of 45
- having a family history of the condition
- getting little or no exercise
- having obesity or overweight, particularly having excess weight around the midriff
- low levels of HDL, or ‘good’ cholesterol
- high levels of triglyceride fats.
People can reduce their risk of developing T2D by maintaining a healthy weight, improving their diet, and being active.
The CDC recommends reducing the intake of processed foods, trans fats, and alcoholic and sugary drinks, instead opting for non-starchy vegetables, fruits, lean proteins, whole grains, water and unsweetened beverages to help reduce risk.
A low carbohydrate diet
The prospective cohort study was conducted on 203,541 men and women in the U.S. over more than 30 years. All participants were free of T2D, cardiovascular disease, and cancers at the start of the study.
Every four years, participants undertook dietary assessments using a validated food frequency questionnaire. The researchers created scores based on the percentage of total energy each person got from their daily intake of proteins, fats, and carbohydrates. They then divided the participants into five groups.
The low-carbohydrate group got around 40% of their total calories from carbohydrates.
The researchers then evaluated the quality of the diets, by classifying 18 groups of nutrients, such as whole grains, fruits, vegetables, nuts, legumes, sweets and desserts, animal fat, dairy, and meat.
“Advantages of the study are the big numbers and long time scale, but the exact quantity of carbohydrates they ate each day was not measured, which could lead to some inaccuracies.” — Dr. Eamon Laird
Plant-based foods lower diabetes risk
Overall, a low-carbohydrate diet did not reduce the risk of T2D. However, when the sources of dietary protein were considered separately, the researchers found considerable differences in T2D risk.
Those who included mostly vegetable protein in their diet had a 6% reduced risk of T2D over the 30 years.
For people who restricted their intake of refined carbohydrates, the risk of T2D was reduced even further, at 15% less than those on a regular diet.
In contrast, those on a low-carbohydrate diet who ate mainly animal protein had a 35% higher risk of T2D, which increased to 39% in those who also ate a diet that was low in whole grains.
Limitations of the study
Dr. Laird pointed out the lack of specificity when it came to the protein sources consumed.
“From the short abstract, there is no information on the types of protein from animal foods (heavily processed usually means higher fats and sugar vs organic/non-processed, that has lower fat and sugars). We also do not know what other lifestyle factors were taken into account?” he said.
Meanwhile, lead study author Yeli Wang noted that their observations were in a cohort that was primarily white. Studies have shown that the risk of T2D is higher in certain other ethnic groups, particularly African Americans, Hispanics, and Native Americans. In the U.S., T2D is almost twice as common in African Americans as it is in non-Hispanic whites.
“We wonder whether our results could be generalized to other ethnic groups. We need to look at that,” Dr. Wang said.
What to eat to reduce diabetes risk
What is known is that maintaining a healthy weight, exercising regularly, and eating a healthy diet with few processed foods help to reduce your risk of developing T2D.
The American Heart Association recommends including a wide variety of fruits and vegetables and healthy sources of protein, such as fish and seafood, legumes and nuts, low fat or nonfat dairy, and lean meats. It encourages choosing minimally processed foods over ultra-processed foods and limiting sugar, salt, and alcohol.
It may be that by opting for plant-based protein, such as nuts, lentils, beans, and soya, in place of animal protein, one could reduce that risk even further.
“Some studies have associated more plant-based diets with healthier lifestyles (such as less smoking, drinking, more physical activity, more supplement use) which impacts [the] risk of diabetes. So we do need to see more information first before jumping to any conclusions.” — Dr. Eamon Laird
This article originally appeared here and was republished with permission.