Researchers looked at 50 different studies involving over 3 million people to understand how fermented foods affect how long we live. Fermented foods are foods that have been broken down by helpful bacteria, like yogurt, cheese, and chocolate. The study found that people who ate more fermented milk products, cheese, and chocolate had lower chances of dying from heart disease and other causes. These foods contain special compounds and good bacteria that may protect our hearts and overall health. However, not all fermented foods showed the same benefits—miso and fermented bread didn’t show clear protective effects.
The Quick Take
- What they studied: Whether eating fermented foods (like yogurt, cheese, and chocolate) is connected to living longer and having fewer deaths from heart disease and cancer
- Who participated: Over 3 million healthy adults from 50 different research studies conducted around the world
- Key finding: People who ate the most fermented milk products, cheese, and chocolate had significantly lower rates of death from all causes and heart disease compared to those who ate the least
- What it means for you: Adding more fermented foods like yogurt and cheese to your diet may help protect your heart and overall health, though these foods work best as part of a healthy lifestyle, not as a replacement for other healthy habits
The Research Details
This is a meta-analysis, which means researchers combined information from 50 different long-term studies to find patterns. Each of the original studies followed healthy people over many years and tracked what they ate and whether they died, and if so, from what cause. The researchers looked at studies that compared people who ate the most fermented foods to those who ate the least. They used a special method called the Newcastle-Ottawa Scale to check if each study was done well and fairly. They then combined all the results using a statistical method that accounts for differences between studies.
By combining so many studies with millions of people, researchers can see patterns that might not show up in smaller studies. This approach is stronger than looking at just one study because it reduces the chance that results happened by accident. Following people over time (rather than just asking them questions once) helps show real connections between what they eat and their health outcomes.
This analysis included a very large number of participants (over 3 million), which makes the findings more reliable. The researchers checked each study for quality and bias. However, because this combines many different studies done in different ways, some differences in how studies were conducted could affect the results. The findings are strongest for fermented milk products and cheese, and weaker for other fermented foods.
What the Results Show
The study found that people who consumed the highest amounts of fermented milk products (like yogurt), cheese, and chocolate had lower rates of death from all causes compared to those who ate the least. For heart disease specifically, higher consumption of these three foods was linked to lower death rates. Fermented milk products showed an additional benefit: people who ate more of them had lower rates of cancer deaths. The protective effects were consistent across the many studies analyzed, suggesting these findings are fairly reliable.
Interestingly, miso (a fermented soybean paste) and fermented bread did not show clear connections to lower death rates. This suggests that not all fermented foods provide the same health benefits. The researchers noted that the benefits may come from different compounds in different foods—some fermented foods are rich in special proteins, others in plant compounds called polyphenols, and all contain beneficial bacteria.
This is described as the first comprehensive meta-analysis looking at fermented foods and death rates. Previous research has suggested that fermented foods are healthy, but this study provides stronger evidence by combining many studies together. The findings align with other research showing that dairy products and chocolate contain compounds that support heart health.
The studies included were observational, meaning researchers watched what people ate but didn’t control their diets in an experiment. This means we can’t be completely sure that fermented foods caused the lower death rates—other healthy habits of people who eat fermented foods might be responsible. Additionally, the studies measured food intake differently, and people’s memories about what they ate might not be perfectly accurate. The benefits shown are associations, not proven causes.
The Bottom Line
Based on this evidence, eating fermented milk products like yogurt, cheese, and moderate amounts of chocolate appears to be a healthy choice that may support heart health and longevity. These foods are best included as part of a balanced diet with plenty of vegetables, fruits, whole grains, and lean proteins. The evidence is moderate to strong for fermented milk and cheese, and moderate for chocolate. These foods should not be viewed as a substitute for other healthy lifestyle choices like exercise and not smoking.
Anyone interested in heart health and living longer should consider including more fermented milk products and cheese in their diet. People with lactose intolerance might benefit from fermented dairy products, which are often easier to digest. Those with specific health conditions should consult their doctor about portion sizes. The findings apply mainly to healthy adults and may not apply to people with certain medical conditions.
The protective effects of fermented foods likely develop over years of consistent consumption, not days or weeks. You might notice improved digestion within days or weeks, but the heart-protective and longevity benefits would take months to years of regular consumption to fully develop.
Want to Apply This Research?
- Track daily servings of fermented foods (yogurt, cheese, fermented milk drinks) and note the type and amount consumed. Aim to log at least one serving daily and track consistency over weeks and months.
- Add one fermented food to your daily routine: start with a yogurt at breakfast, cheese as a snack, or a fermented milk drink. Make it a habit by pairing it with an existing daily activity (like breakfast or lunch).
- Monitor weekly consumption patterns and create a goal to eat fermented foods at least 5 days per week. Track which types you prefer and which are easiest to include in your routine. Over months, note any changes in how you feel, energy levels, and digestive health as secondary indicators of benefit.
This research shows associations between fermented food consumption and lower death rates, but does not prove that fermented foods directly cause these benefits. Individual results may vary based on overall diet, lifestyle, genetics, and health status. People with lactose intolerance, dairy allergies, or specific medical conditions should consult their healthcare provider before significantly increasing fermented food intake. This information is for educational purposes and should not replace professional medical advice. Always consult with a doctor or registered dietitian before making major dietary changes, especially if you have existing health conditions or take medications.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.