A daily regimen of kefir, a fermented milk drink, has been associated with significant improvements in gut health, a reduction in acid reflux, and modest weight loss, according to a personal trial. The beverage, which has seen a resurgence in popularity, is made by fermenting milk with kefir grains, a mix of beneficial bacteria and yeast.
Historically, fermented milk consumption was linked to longevity, with Russian physician Dr. Elie Metchnikoff proposing the idea in 1905. Today, kefir is consumed in the UK, with annual sales reaching £40 million. Brands market it with claims of boosting the immune system, strengthening bones, and enhancing brain function, while studies suggest potential benefits for cardiovascular health, digestion, and weight management.
To investigate these claims, a month-long experiment involved drinking 250ml of Biotiful kefir daily. Initial health assessments revealed low gut microbial diversity, elevated LDL (bad) cholesterol, and a BMI of 27, placing the individual in the overweight category. Symptoms of daily acid reflux and bloating were also reported.
Health Improvements Observed
After two weeks of consistent kefir consumption, daily acid reflux symptoms ceased. Nutritionist Dr. Federica Amati, from Imperial College London, suggests this could be due to improved diversity in the colon, which may positively impact the upper gastrointestinal tract.
By the end of the four-week trial, a weight loss of nearly 9 pounds was recorded, moving the individual closer to a healthy BMI. This weight loss is attributed to reduced snacking, as the kefir, approximately 150 calories with 8g protein and 8g fat per serving, provided a feeling of fullness. Some research indicates that fermented foods may influence appetite-regulating hormones like GLP-1, though further evidence is needed.
Follow-up gut microbiome tests showed an increase in microbial diversity, from 134 to 147 species, and a decrease in 'good' bacteria deficiencies. While some studies suggest kefir can reduce cholesterol, no change was observed in the participant's cholesterol levels after one month. The evidence for kefir's cholesterol-lowering effects is mixed, and full-fat versions may contain saturated fat.
Expert Recommendations
Experts recommend incorporating fermented foods into the daily diet. Dr. Amati suggests aiming for three servings of fermented foods daily, with 250ml of kefir considered equivalent to three servings. Other fermented options include miso, kimchi, or adding kefir to breakfast cereals.
When selecting kefir, consumers are advised to check labels for added sugars and opt for plain varieties to control flavorings and sugar content. Increasing fermented food intake, alongside fiber, is considered important for overall health. The trial participant found the daily kefir habit beneficial and intends to continue it.
