newly Nutrients A study in the Journal of Nutrition evaluated how the combination of mediterranean diet (MedDiet) supplementation and dairy foods affected the gut microbiome of Australians at high risk for cardiovascular disease (CVD).
Stady: Interactions between a dairy-supplemented Mediterranean diet and gut microbiota affecting cardiovascular health in an Australian population.. Image credit: Divi Art/Shutterstock
Diet plays an essential role in regulating immunity and maintaining metabolic health. Improper diet is often associated with the development of obesity, cardiovascular disease and type 2 diabetes. Long-term adherence to a specific dietary pattern helps shape the gut microbiota. Gut microbes produce many bioactive compounds by metabolizing food components, influencing host metabolism and immune homeostasis.
Gut microbes produce short-chain fatty acids (SCFAs), such as acetate, butyrate, and propionate, through fermentation of indigestible fiber. These SCFAs are the main sources of energy for colon tissue to modulate inflammatory pathways, maintain gastrointestinal tissue integrity, and inhibit the proliferation of pathogenic bacteria. Changing certain bacteria in the gut lowers triglyceride levels, reduces markers of systemic inflammation (such as C-reactive protein), and improves liver function.
All intestinal microbial products are not beneficial to humans. For example, microbial metabolism of L-carnitine and choline leads to the production of trimethylamine N-oxide (TMAO), a metabolite associated with manifestations of atherosclerosis and inflammation. Both carnitine and choline are commonly found in nuts, dairy products, meat, fish, and eggs.
MedDiet contains fruits, vegetables, nuts, extra virgin olive oil (EVOO), legumes, and grains. This type of diet recommends consuming moderate amounts of fish, dairy products, eggs, poultry, and red wine. Furthermore, the MedDiet is associated with reduced consumption of red meat, processed foods, and discretionary foods (such as cakes and sweets).
An abundance of bioactive nutrients, such as fibre, polyphenols, vitamins, minerals, antioxidants and monounsaturated fats, has been associated with the MedDiet, which promotes beneficial effects through the gut microbiome. Long-term adherence to the MedDiet significantly improves obesity, metabolic syndrome, diabetes, and dyslipidemia.
It should be noted that the typical MedDiet provides calcium well below the Australian Recommended Daily Intake (RDI). Calcium plays an important role in bone formation and maintenance, blood vessel dilation and contraction, cell differentiation, nerve cell activity, and cell signaling for muscle function. Inadequate calcium intake leads to decreased bone strength and promotes pregnancy complications. It also increases the risk of cardiovascular disease. A MedDiet supplemented with dairy products, such as milk, yogurt and cheese, would meet the Australian Calcium Intake Recommendations. It is essential that the MedDiet meets all nutritional requirements prior to recommendation.
About the study
The current randomized controlled trial (RCT) followed a 2 × 2 crossover design to compare the benefits of MedDiet supplemented with dairy foods (MedDairy) and low-fat diet (LFD) (control) in Australians at risk of cardiovascular disease.
This study recruited adults between the ages of 45 and 75. All participants had high systolic blood pressure (SBP) but were not on any medication. Individuals who took medical levels of daily calcium or omega-3 supplements were excluded.
Participants were randomly assigned to either group, i.e., MedDairy (Group 1) or LFD (Group 2), and the dietary interventions continued for 8 weeks, separated by an 8-week washout phase during which participants followed their usual diet. Complete fecal and clinical samples were collected at baseline and after 8 weeks to evaluate both groups.
At baseline, there were no significant differences between the study groups. The first group included 18 participants, and the second group included 16 participants. All participants who did not follow a MedDiet at baseline showed increased adherence to a MedDiet with the MedDairy intervention. Along with the MedDiet, participants received 3 to 4 servings of any dairy products, such as low-fat Greek yogurt, low-fat milk, cheese (hard, soft, and semi-soft), and tzatziki sauce.
The analysis of fecal microbiota indicated that there was no significant difference in the general structure and composition of the fecal microbiota between the two study groups. However, a modest decrease in microbial diversity was observed in the LFD group. Of note, the MedDairy diet did not significantly alter the gut microbiota but significantly altered the abundance of selected bacterial taxa, such as butyricacocus, Lachnospiraceaestreptococcus, low in colinsella And Philonella.
The results of the current study highlighted that 8 weeks of a Mediterranean diet supplemented with dairy foods led to changes in the relative abundance of some bacterial taxa. MedDairy Diet Enhancement butyricacocus, Which has a positive effect on systolic blood pressure. Therefore, adherence to the MedDairy Diet can reduce the risk of cardiovascular disease.