Over the last few decades, there’s been growing scientific interest in the potential health benefits of yogurt.
However, the idea that yogurt might be good for you isn’t new. Indian scripts dating back around 8,000 years describe health benefits of fermented milk products.
Similarly, nomadic Turks in the 11th century used yogurt to treat diarrhea, cramps, and sunburn. And Genghis Kahn fed his army yogurt, believing it made them brave.
Of course, not all ancient medical knowledge holds water — see bloodletting and leech therapy — but the view of yogurt might have been closer to the mark.
In this article, we’ll take a look at growing evidence that yogurt might reduce the risk of developing type 2 diabetes.
What’s in yogurt?
Yogurt is a good source of protein, with around 8 grams in 100 g of yogurt. It also contains all nine essential amino acids and a healthy dose of vitamins and minerals, such as calcium.
Another important component of yogurt is its microbial load — just a single serving contains billions of bacteria.
The most common species in yogurt are Streptococcus thermophilus and Lactobacillus bulgaricus. But it can also include others, such as L. acidophilus, Bifidobacterium bifidum, B. lactis, L. casei, and L. rhamnosus.
Although some bacteria are killed in your stomach's hostile, acidic environment, enough make it to the furthest stretches of your colon to interact with your gut microbiome.
Yogurt and diabetes
Over the years, there has been a fair amount of interest in links between yogurt and diabetes. And some of the findings are encouraging.
For instance, a review from 2017 looked at 13 studies investigating links between yogurt and type 2 diabetes. Overall, the authors concluded:
“The large-scale and robust evidence strongly suggests that yogurt consumption may protect against the development of type 2 diabetes and that it can be incorporated into a healthy dietary pattern.”
Meanwhile, a meta-analysis from 2016 explored links between dairy in general and type 2 diabetes.
The conclusions point to a “possible role for dairy foods, particularly yogurt, in the prevention of [type 2 diabetes].”
Specifically, the researchers found that individuals who consumed 80 g of yogurt each day had a 14% lower risk of diabetes than people who ate no yogurt.
However, there were no further reductions in risk at higher intakes, when people consumed more than 80 g per day.
It’s worth noting that not all studies have identified benefits. For instance, a study involving 59,000 Black women in the United States found no protective effects of yogurt against type 2 diabetes.
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Also, the evidence that yogurt can benefit people already living with diabetes is less sound.
A review of nine studies investigated whether yogurt affected insulin or blood sugar levels. The scientists also assessed insulin resistance. This is when your cells don’t respond to insulin as effectively, so less sugar moves from your blood into your cells.
Overall, the authors didn’t find good evidence that eating yogurt improved any of these measures.
But they did note that in five of the nine trials, the researchers used regular yogurt as a control. And it’s possible that regular yogurt improves blood sugar control, so this makes it difficult to interpret the results.
So, although the evidence is incomplete, yogurt might reduce diabetes risk for some people. If so, how might that work?
Scientists have different theories about how yogurt might reduce diabetes risk. Below, we’ll touch on a few of them.
Preventing weight gain
Overweight and obesity don’t directly cause type 2 diabetes, but they’re a risk factor for the condition. And a few studies suggests that yogurt is associated with reduced weight gain.
Some scientists think that the calcium in it might partly explain why yogurt could protect against weight gain. However, the evidence that calcium is linked to weight gain isn’t compelling.
Perhaps yogurt’s high protein content helps manage weight. Protein keeps you fuller for longer, so it might help reduce your overall food intake.
However, studies linking yogurt to reduced weight gain only identify an association rather than causation. So, other factors could be involved, not just the yogurt.
Also, the reduction in weight gain in these studies was small — perhaps not enough to make a difference to diabetes risk.
So, what else might be playing a part?
Some studies looking at yogurt and diabetes accounted for body mass index (BMI) in their analyses. Yogurt was still associated with a lower risk of diabetes, regardless of participants' BMI.
In other words, body weight can’t be the whole story.
Some scientists think calcium might influence insulin directly. They explain that higher calcium levels in cells might encourage insulin release.
More insulin being released would reduce blood sugar levels and potentially protect against type 2 diabetes.
Also, consuming yogurt is associated with increased levels of two compounds, called glucagon-like peptide 1 and peptide YY. Both reduce appetite and influence glucose metabolism, so they could also play a part.
These theories are all good, but scientists don’t yet know which combination of these factors, if any, is doing the heavy lifting.
Importantly, yogurt isn’t the only food that contains calcium and protein — other dairy products do, too. And drinking milk is also associated with increased levels of glucagon-like peptide 1 and peptide YY.
Still, in multiple studies, yogurt comes out on top in terms of diabetes prevention. So the question is: What’s special about yogurt, compared with milk, butter, or cheese?
What sets yogurt apart?
Live yogurt contains microbes. This may be the secret to yogurt's protective effects, compared with other dairy.
Within each of us, there are trillions of microorganisms collectively known as the gut microbiome. Scientists have linked these microscopic lifeforms to many aspects of health and disease.
And there’s evidence that eating yogurt can alter your gut microbiome in a positive way.
But how could bacteria in your gut influence diabetes? There are multiple threads of evidence, but scientists are still trying to knit them together.
Diabetes and gut bacteria
The first thread is that people with type 2 diabetes have gut microbial dysbiosis. In general terms, dysbiosis means that your gut microbiome is out of balance in a way that is linked to poorer health outcomes.
Dysbiosis might mean that you have fewer “good” bugs and more “bad” bugs.
So, you can imagine that if yogurt promotes “good” gut bacteria, it could potentially reduce diabetes risk.
However, it’s not clear whether gut bacteria drive diabetes or whether changes associated with diabetes — like different eating habits — drive the changes in gut bacteria.
The relationship likely runs in both directions, and some mouse studies offer fascinating insights.
For instance, in one study, researchers transferred poop, containing gut bacteria, from a healthy mouse to a mouse with diabetes.
After the transfer, the diabetic mouse had improved insulin resistance, and its levels of inflammation decreased.
So, by “upgrading” the mouse’s gut microbiome, signs of diabetes improved. Although it works in mice, that certainly doesn’t mean it’ll work for you, but it’s compelling stuff.
Diabetes and inflammation
Another thread is inflammation, which is tightly linked to diabetes. The precise role of inflammation in diabetes is unclear, but some scientists think it damages the cells that produce insulin, steadily worsening the condition.
A healthy gut microbiome is associated with reduced inflammation, and an unbalanced microbiome is associated with increased inflammation.
So, once again, if yogurt benefits your gut microbiome, it could reduce inflammation and, therefore, reduce diabetes risk. Potentially.
Taken together, these threads certainly don’t prove that yogurt reduces the risk of developing type 2 diabetes, but they show how it might be possible.
They also underline the dizzyingly complex links between food, gut bacteria, inflammation, and health. Scientists are still just beginning to explore how these threads knit together.
The end product
Whether regularly consuming yogurt reduces diabetes risk or not, yogurt can certainly be a healthy part of your diet. If you like the taste, add it to your grocery list.
We asked Emily Leeming, Ph.D., ZOE’s senior nutrition scientist, which yogurts are best in general:
“When choosing yogurt, it’s best to avoid low-fat versions — they often come with added sugars. Having full-fat yogurt also helps you feel fuller for longer. "
"Also, go for plain or Greek rather than fruit-flavored. If you do feel like flavored yogurt, choose one with real fruit added to it by checking the back of the pack.”
“And opt for ‘live’ yogurt to know you're getting that probiotic goodness.”
With type 2 diabetes now affecting an estimated 11.4% of the U.S. population, scientists will no doubt continue investigating.
And because yogurt is readily available and can form part of a balanced diet — if it does help reduce diabetes risk, it would be a simple, convenient intervention.
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