The title of this article is a question I get asked a lot! And for a good reason. Traditional diabetic diets encourage lower carbohydrate foods like lean proteins, low-fat dairy while limiting carbohydrates like grains, beans, legumes and fruits. Plant-based diets are amazing for stopping the progression of kidney disease (and can even improve kidney function in some). Check out my post on how plant-based diets help with chronic kidney disease if you haven't already: https://www.lindsaynutrition.com/post/how-plant-based-diets-can-help-your-kidneys.
The short and sweet answer to the above question is: plant-based diets are best for BOTH diabetes and CKD! Sounds crazy, I know, but hear me out. In this article I'll go over the cause of diabetes and what makes plant-based diets so great at improving diabetes.
One of top causes of CKD is diabetes. According to the World Health Organization, 95% of people with diabetes have type 2. I'll be referring to type 2 diabetes throughout this article. (Although type 1 can also benefit from plant-based diets.) As I mentioned above, traditional diabetic diets focus on limiting carbohydrates. This is because when we eat carbohydrates, it eventually break down into glucose, which is blood sugar. Sources of carbohydrates include table sugar/sweeteners, desserts, soda/juices, cereals, pastas, breads as well as healthy foods like beans, legumes, whole grains and fruits. Diabetic diets typically encourage animal protein and dairy as they have less carbs.
Plant-based diets are typically higher in carbohydrates, especially from starchy plant foods like legumes, beans, fruits and whole grains. This eating pattern contains little to no animal products like dairy, meat and seafood. How strictly one limits animal foods can vary based on personal preference and health goals. A plant-based diet focuses on minimally processed foods (like choosing beans as a protein for the meal rather than a Beyond burger or other vegan "meats").
To best understand how a plant-based diet can help improve, and even reserve, type 2 diabetes, it's important to understand the actual cause of this condition.
Let’s talk about insulin. Insulin is what helps control the level of glucose in our blood. Our body likes to maintain a blood sugar level of about 70-126 mg/dL. In normal circumstances, when blood glucose goes up, like after eating a meal, insulin is released. Think of insulin as a key. It unlocks cells in the body to let blood glucose inside so I can be used for energy.
In type 2 diabetes, insulin resistance occurs. This is when insulin is released but the cells aren’t responding properly to it. The key (insulin) is trying to "unlock" the cell to let glucose in, but the lock is stuck. With the insulin unable to open up the cells, glucose stays in the blood and blood sugar becomes elevated. When blood glucose levels are high, glucose deposits where it shouldn’t, like in blood vessels. The long-term accumulation of glucose in the tiny vessels in the filtering units of the kidneys is what leads to chronic kidney disease.
You may be wondering, why aren't the "locks" on the cells able to open? It’s because saturated fat and LDL cholesterol has accumulated inside them. Research has shown that plant-based diets can actually clear out this fat stuck inside the "lock" (1). Reducing the fat inside the cells will restore the cells ability to let insulin “unlock” the cell and let glucose enter into the cell, thus improving insulin resistance.
There are several aspects of a plant-based diet that can improve diabetes. One important factor is what a plant-based diet lacks which is bad cholesterol and saturated fat. With the exception of coconut and palm oil, plant-foods are generally low in saturated fat and contain no cholesterol.
Plant foods like nuts/seeds, olives, avocado and plant oils are high in unsaturated fat, which is actually beneficial for reducing cholesterol and do not lead to insulin resistance like saturated fats do. Although unsaturated fat is considered a “healthy” fat, it still needs to be consumed in moderation as it is very calorie dense. Working with a registered dietitian can help you make sure you are consuming the right amount of healthy fat.
Plant-based diets promote high fiber foods. Fiber is a type of carbohydrate that your body cannot digest and is only found in plant foods. Good sources of fiber include whole grains, vegetables, fruits and plant-proteins like beans, lentils, soy beans, nuts and seeds. Fiber has been shown to improve satiety, aid in weight loss and reduce inflammation. Another benefit of fiber is that it’s beneficial for our gut - healthy gut bacteria also help our bodies process glucose like it should. The American Diabetes Association recommends fiber intake of 25 mg/day for woman and 38 mg/day for men. Plant-based diets often provide over 40 g fiber per day. It’s always a good idea to increase fiber content slowly to avoid any gastrointestinal discomfort.
Another way plant-based diets can help benefit diabetes is the fact is it rich in vitamins, minerals and antioxidants. Plant foods are a good source of magnesium which is linked to insulin sensitivity (2). Plants contain special phytochemicals, which are antioxidants found only in plant foods, which have also been linked to improvements in blood sugar control (3).
Eating a higher carbohydrate plant-based diet may seem a little scary as low carb diets are pounded into our minds as the only way to manage diabetes... but I hope this information helps change your mind. There are some dietary considerations to be taken into account for someone with both diabetes and chronic kidney disease, such as total protein intake, but it makes things easier knowing you can follow basic plant-based diet principles if you have both conditions. If you want assistance with managing your diabetes and chronic kidney disease with nutrition, feel free to reach out!
Goff LM, Bell JD, So PW, Dornhorst A, Frost GS: Veganism and it’s relationship with insulin resistance and intramyocellular lipid. Eur J Clin Nutr 59:291-298, 2005
Ley SH, Hamdy O, Mohan V, et al. Prevention and management of type 2 diabetes: dietary components and nutritional strategies. Lancet. 2014;383:1999–2007.
Kim Y, Keogh JB, Clifton PM. Polyphenols and glycemic control. Nutrients. 2016;8:17.