Dairy for Metabolic Syndrome Management

Probiotic Kefir is Beneficial for Metabolic Syndrome Management.jpg

Dairy for Metabolic Syndrome Management

Metabolic syndrome is a cluster of interrelated risk factors including obesity, especially visceral obesity, impaired glucose tolerance, insulin resistance, hyperlipidemia, and hypertension. Dairy foods can be beneficial for the management of metabolic syndrome, with the benefits such as reducing appetite and improving postprandial glycemic response.

One study examined various dairy foods in amounts usually consumed on satiety and postprandial glucose and insulin levels in either young or older adults (1). In this randomized crossover study, 30 healthy young adults (age: 23.5 ± 0.5 years; body mass index (BMI): 21.8 ± 0.4 kg/m2) and 30 healthy/overweight older adults (age: 65.2 ± 0.5 years; BMI: 24.7 ± 0.6 kg/m2) consumed 1 serving (according to manufacturers' labels) of skim milk (0.1% milkfat), whole milk (3.25% milkfat), plain Greek yogurt (2% milkfat), cheddar cheese (31% milkfat), and water (energy-free control) after a 12-hour fast. Subjective appetite was measured every 15-30 min over 3 hours. Blood glucose and insulin were measured at baseline and every 15-30 min over 2 hours.

All dairy treatments reduced post-treatment subjective appetite area under the curve over 3 hours by 8%-17% more than water. Greek yogurt reduced appetite 3-hour area under the curve more than skim and whole milk by 9% and 7%, respectively (p < 0.0001). Post-treatment blood glucose 2-hour area under the curve was 42% lower in young compared with older adults (p = 0.003). It was also 52%-78% lower after cheese compared with kinds of milk and yogurt (p < 0.0001). Post-treatment insulin area under the curve after the cheese was only 10%-15% of that after kinds of milk and Greek yogurt (p < 0.0001). The study showed that single servings of dairy differ in effect on postprandial satiety and glycemia, but they are all beneficial for the management of metabolic syndrome (1).

The development of the metabolic syndrome and related chronic disorders is believed to involve chronic low-grade systemic inflammation with progressive immune cell infiltration into adipose tissue. The impairment of intestinal wall integrity had been suggested as an important factor contributing to the low-grade chronic inflammation such as in obesity and metabolic syndrome. The effect of dairy food supplementation on intestinal wall permeability was examined in overweight adults.

In a crossover study, 28 overweight adults were randomized to start one of the two phases, either a 3-week kefir (fermented milk) supplementation or a 3-week milk supplementation, which was followed by the other phase after a 7-day washout period (2). Compared with the milk supplementation, kefir supplementation resulted in a greater improvement of serum zonulin levels. Zonulin is a protein that regulates intestinal permeability and a higher level of zonulin is commonly used as a serum marker of compromised intestinal wall integrity.

Both kefir and milk supplementations significantly improved lipid profile and glucose levels. Positive mood was slightly but significantly enhanced with kefir supplementation, and reduced with milk supplementation. Supplementation with both dairy products had health-beneficial effects, but only kefir showed an effect on the intestinal barrier dysfunction marker zonulin (2).

The beneficial effects of kefir on intestinal integrity may be related to an alteration in the intestinal microbiota. Reduced intestinal permeability could reduce oxidative stress and low-grade chronic inflammation.

Dairy has many health benefits, including its most known one for healthy bone development and maintenance. As a nutrient-dense food category, dairy has been recommended to be included in a healthy diet for young and old. Dairy foods have the benefits of reducing glucose, insulin resistance, lowering lipid levels, curbing the appetite, reducing oxidative stress and inflammation. I see dairy foods, especially fermented probiotic-containing dairy foods such as yogurt and kefir, have great potential to have many value-added offerings and varieties with many health benefits, including one for metabolic syndrome management.