According to DairyReporter, a cohort study conducted over a period of 9 years found evidence that consumption of full-fat dairy may be linked to reversing hyperglycemia and preventing its progression to type 2 diabetes in prediabetic patients.

A Success for Researchers

There was no previous evidence linking dairy consumption to the chance of prediabetes remission, i.e., a reversal of the condition preceding type 2 diabetes.

Researchers from Shahid Beheshti University of Medical Sciences in Tehran, Iran, published the results of a 9-year longitudinal study on how the consumption of full-fat dairy products affected the chances of reversing prediabetes or developing type 2 diabetes.

In particular, the authors found that consuming full-fat yogurt may be associated with a lower chance of developing diabetes and an increased likelihood of returning to normal glycemia - that is, normal blood sugar levels - for patients who already had prediabetes. The effects of other dairy products on glycemic health were less clear, with contradictory results regarding the consumption of yogurt, cream, butter, and low-fat cheese.

The research was conducted on 334 prediabetic patients, who were part of the Tehran Lipid and Glucose Study, a community-based prospective study that began in 1999. Participants' data, including biochemical measurements and dietary assessment, were collected in 2006-2008 with follow-ups taking place in 2009-2011; 2012-2014, and 2015-2017.

The average age of the cohort was 49.4 ± 12.8 years, and 51.5% were men; the rate of prediabetes progression and regression was similar (39.8%), although those who returned to normal glycemia were younger and had lower blood sugar levels, body mass index, and cholesterol ratio.

Results

During the follow-up, researchers found that participants who consumed large amounts of full-fat dairy products (more than 230 g per day) had significantly lower fasting and 2-hour serum glucose concentrations over time.

"In our study, the amount of yogurt consumed was significantly higher from the dietician's point of view in subjects who returned to normal glycemia compared to those who remained [prediabetic], and higher yogurt intake was associated with the reversal of prediabetes to normal glycemia."

The opposite was true for higher cheese intake (more than one serving per day), which was associated with higher 2-hour glucose concentrations; while high milk consumption was linked to decreased 2-hour glucose levels over time.

Regarding the effects of dairy consumption on prediabetes reversal, "the chance of returning to normal glycemia was significantly increased" when consuming 200 g of high-fat dairy per day.

Specifically, higher yogurt intake seemed more likely to be associated with returning to normal glycemia, while high cheese intake was more likely to increase the risk of developing type 2 diabetes in prediabetic patients.

Overall, the authors concluded that regular consumption of dairy may increase the chances of prediabetes regression to normal glycemia.

Yogurt, a "superfood" for diabetics

Consumption of basic dairy products, such as full-fat yogurt, appears to be associated with a lower risk of type 2 diabetes in some studies, but researchers are far from clear why this seems to be the case.

Last month, the Food and Drug Administration concluded that there is enough evidence to support a qualified health claim that regular yogurt consumption may reduce the risk of developing type 2 diabetes.

The decision, which followed five years of petitions by leading dairy producer Danone North America, means that food manufacturers can now use an FDA-supported claim on the label - but the evidence supporting it remains "limited," according to the FDA.

Regardless, academic literature supporting the positive effects of full-fat dairy on glycemic health continues to emerge – although there is no scientific consensus on what makes dairy so beneficial.

"The causality and mechanisms underlying the observed relationships between dairy consumption and the risk of [type 2 diabetes] in cohort studies remain unclear," explain the researchers from Shahid Beheshti University of Medical Sciences in their paper, adding that there were no other available evidence linking dairy products to the chance of regression from prediabetes to normal glycemia.

Complicated Research

Existing research on cheese is even more complicated, with some findings supporting that consumption may reduce the risk of developing diabetes, while others have not found such evidence.

"A possible adverse effect of high cheese consumption on glucose metabolism is supported by evidence indicating that dietary patterns with high cheese consumption increase the risk of gestational diabetes, obesity, and abdominal obesity," summarize the authors.

So why isn't there scientific consensus on why yogurt seems to be good for glycemic health?

The inconsistent findings, say the authors, could be due to the unique composition of cheese and yogurt, the variety of dairy products available globally, and how these foods are consumed in different cultures – e.g. cheese on pizza versus fresh goat cheese in a salad.

However, current findings suggest that regular dairy consumption may reduce the risk of developing type 2 diabetes or may improve the chances of reversing prediabetes. The work also provides some evidence against claims that high-fat dairy may be a risk factor. (Photo: Dreamstime)

(Source: Usual intake of dairy products and the chance of pre-diabetes regression to normal glycemia or progression to type 2 diabetes: a 9-year follow-up. Bahadoran, Z., Mirmiran, P. & Azizi, F. Nutr. Diabetes​ 14, 15 (2024).)