Globally, 537 million adults or 1 in 10 adults, aged 20-79 years old, live with diabetes. Over the next 22 years, this number is projected to rise to 783 million (1). Diabetes increases the risk of developing cardiovascular diseases such as coronary artery disease, heart attack, and stroke (1-5). Type 2 diabetes—which prevents proper regulation and use of insulin by the body, resulting in high blood sugar levels—accounts for more than 95% of all diabetes cases (5). People living with type 2 diabetes are at least two times more likely to develop cardiovascular disease and die from it than those living without diabetes (6).
As a result of these negative implications, people living with type 2 diabetes should actively work to lower their risk of cardiovascular disease. One approach is through diet—what we eat or drink, how much of it, at what frequency, and more.
The importance of diet is not lost on us. Be it prevention or treatment, consuming a nutritious and well-balanced diet is one of the most heavily prescribed lifestyle interventions for maintaining or improving our health and well-being. One systematic review investigated the impacts of seven dietary patterns on improving cardiovascular risk factors in people with type 2 diabetes compared to no intervention. Outcomes included average blood sugar levels, systolic blood pressure, low-density lipoprotein (LDL) “bad” cholesterol, and major adverse cardiovascular events. Here, no intervention consisted of people following their usual diets or receiving one-time dietary advice. The table below describes the seven diets studied (2).
| Diet | Description |
|---|---|
| Low glycemic index (GI) diet | Consuming foods that result in slower and smaller increases in blood sugar levels and are high in fiber |
| Mediterranean diet | Focuses on the consumption of fish, lean meats, whole grains, fruits, vegetables, and plant-based oils |
| Plant-based diet | Vegan (no animal products) or vegetarian |
| High protein diet | Equal to or more than 25% of one’s caloric intake comes from protein |
| Low carbohydrate diet | Less than 30% of one’s caloric intake comes from carbohydrates |
| Low fat diet | Less than 30% of one’s caloric intake comes from fats |
| Moderate carbohydrate diet | More than 45% of one’s caloric intake comes from carbohydrates, more than 30% is from fat, and less than 25% is from protein |
What the research tells us
Overall, the review found positive results across all diet types—mainly in the short-term—for some outcomes but not others.
All or almost all the diets were associated with weight loss and improved blood sugar levels in the short- term (6 months), but generally, these findings were not maintained in the longer term (12 months). The Mediterranean diet was the only one to report improved weight at 12 months. When it comes to improving systolic blood pressure and LDL “bad” cholesterol, no short-term or long-term benefits were seen.
The review authors also noted that while only the low GI diet produced a statistically significant reduction in the risk of major adverse cardiovascular events (aka MACE), all the diets showed a trend toward clinically meaningful reductions for this outcome. MACE was estimated based on changes in average blood sugar levels, systolic blood pressure, and LDL-cholesterol 6 months following the start of the diet.
Lastly, although certain diets outperformed others for the outcomes discussed above, no one diet reigned supreme. Ultimately, there was not enough evidence to conclude that one diet was best and should be recommended over the rest. More long-term research is needed (2).
Remember not all diets are safe for all people, some diets should not be practiced in the long-term, and more research on the long term effectiveness and safety of many diet types is still needed. As such, based on the current information, the review authors recommend that the current goal should be about moving towards consuming a nutritious diet overall (2). Prior to making any changes to your diet, consult your healthcare team about a plan that is safe for you and encourages you to stick to your goal.
