More than 5.7 million Canadians have diabetes and about 90 percent have type 2 diabetes. An additional six million Canadians are living with prediabetes—a condition that can develop into type 2 diabetes if it’s not properly managed.^1,2,3

Prediabetes and type 2 diabetes (T2D) can be managed with combination of proper nutrition, physical activity, stress reduction, medication (when needed) and careful blood sugar monitoring.⁴  

The dietary pattern for diabetes prevention and management includes:

• Choosing healthy proteins.

• Opting for low-glycemic carbohydrates, such as whole grains, legumes, vegetables and fruit.

• Choosing more whole foods and fewer ultra-processed foods.

• Limit sugars and sweets.⁵

This article will explore the role of milk and dairy foods in the prevention of T2D. It includes the potential mechanisms through which milk and dairy foods may play a role in reducing the risk of developing type 2 diabetes.

Overview of the nutrients in milk

Milk contains protein and 14 essential vitamins and minerals including:

• Vitamin A

• B vitamins: B1, B2, B3, B5, B6, B12

• Vitamin D

• Calcium

• Magnesium

• Phosphorus 

• Zinc

• Potassium

• Selenium

Fat in milk

Dairy foods likely protect against T2D due to their combination of calcium, magnesium, vitamin D and protein, which help reduce body fat and insulin resistance.⁶  There is no evidence that saturated fat from full-fat dairy foods is associated with an increased risk of insulin resistance or T2D.⁷  In fact, a meta-analysis showed that a high intake of dairy foods was associated with a significant decrease in the risk of T2D.⁸  

Lactose in milk

Milk contains a naturally occurring sugar called lactose. Lactose has a glycemic index (GI) of 46, which is considered low.⁹  The GI is a scale that ranks carbohydrate-containing foods and beverages by how much they raise blood sugar levels. Diabetes Canada advises choosing foods with a low glycemic index (<55) most often, since low GI diets may decrease risk of type 2 diabetes. 

Cow’s milk (skim, 1%, 2% and whole) and plain yogurt are low GI.¹⁰  What accounts for the low GI status of milk and yogurt? A combination of things, including 

• Lactose is naturally low-GI.

• A high protein content.

• The dairy matrix, which helps control gastric emptying.¹¹  

Research on the link between milk and T2D

Type 2 diabetes risk reduction: 

Many studies have shown a reduced risk of developing type 2 diabetes in people who consume sufficient dairy foods.^12,13,14,15

A meta-analysis looked at 21 studies and a total of 44,474 T2D cases. The analysis showed a significant inverse association in developing diabetes in those who consumed more dairy vs. least dairy. Each additional daily 200 g of dairy products was inversely associated with diabetes risk.¹⁶  Other studies have shown that 200-400 grams of dairy foods daily are linked to the largest reduction in T2D risk.^17,18 

A narrative review of cohort studies suggests up to a 15 percent decrease in the risk of developing T2D in people who have three servings of dairy foods per day.¹⁹  The benefits are attributed primarily to a low-fat dairy, yogurt and possibly to cheese. Another meta-analysis found high-quality evidence linking intakes of low-fat dairy and yogurt with a reduced risk of T2D.²⁰ 

Studies also indicate that total intake of dairy foods, including whole-fat dairy foods like milk, cheese and yogurt, is associated with a lower risk of T2D and lower risk of high blood pressure.^21,22  Another study found that high-fat dairy was protective against prediabetes, while neutral associations were seen for low-fat dairy types.²³  

Why do dairy foods help reduce T2D risk?

Some of the main risk factors for developing T2D are hypertension, metabolic syndrome and obesity. Since dairy products can contribute to reducing these risk factors, they also help reduce T2D. Here are some mechanisms at work:

• Fats: Dairy-derived fatty acids are associated with less insulin resistance. Studies also show that certain fatty acids in dairy, such as pentadecanoic acid and heptadecanoic acid, are associated with lower blood sugar levels (in oral glucose tolerance tests).²⁴   Vitamin K2: Some dairy foods contain vitamin K-2, which can improve insulin sensitivity.²⁵ 

• Calcium, magnesium and vitamin D: These nutrients work synergistically by controlling insulin resistance, pancreatic beta-cell function and inflammation.^26,27

• Probiotics and bioactive compounds: Fermented dairy (especially yogurt) is associated with reduced risk of developing T2D due to the presence of probiotic bacteria.²⁸  Fermentation of dairy foods with bacteria generates bioactive peptides, which have a beneficial effect on metabolic health, and may help improve blood cholesterol and fasting blood glucose levels.²⁹

• Protein: The amino acids and bioactive peptides from milk proteins may help delay gastric emptying and enhance the insulin response, which helps lower postprandial glucose levels.³⁰

Practical tips:

Consuming dairy foods within a balanced diet can help lower risk for T2D. When patients ask for nutrition advice for diabetes prevention, start with these tips.

• Refer to a registered dietitian for personalized advice

• Choose whole foods more often than highly processed foods.

• Build meals using these proportions: ½ plate vegetables and fruit; ¼ plate whole grains; ¼ plate protein.³¹ 

• Aim for 2-3 servings of milk or dairy products each day. 

There’s high-quality scientific evidence to show that dairy foods are associated with a reduced risk of T2D. Patients can be advised to enjoy consuming dairy foods within a balanced diet, and get the benefits of nutrients such as protein, calcium, vitamin D, dairy fat and bioactive compounds. The protective role of dairy in the development of T2D is thought to be largely attributable to the dairy matrix.