New Delhi: A plant-rich Green Mediterranean (Green-MED) diet may improve heart and metabolic health while helping offset the effects of a common genetic variation linked to impaired folate metabolism, according to a new international clinical study.

The findings, published in the journal Clinical Nutrition, suggest that people following the Green Mediterranean diet recorded significantly higher blood folate levels than those adhering to a traditional Mediterranean diet or standard healthy eating guidelines. Researchers also found that higher folate levels were associated with better insulin sensitivity, reduced inflammation, healthier blood lipid levels, and lower accumulation of visceral and liver fat.

The study adds to growing evidence supporting the role of nutrition in influencing not only metabolic health but also gene activity through a field known as precision nutrition.

Green Mediterranean diet differs from the traditional plan

The Mediterranean diet is widely recognised as one of the healthiest dietary patterns. It focuses on fruits, vegetables, legumes, whole grains, nuts, olive oil, fish and lean proteins, while limiting processed foods, red meat and added sugars.

The Green Mediterranean diet builds on this foundation by placing greater emphasis on plant-based foods rich in polyphenols and plant protein.

Participants in the study also consumed a daily shake containing mankai (Wolffia globosa), commonly known as duckweed, an aquatic plant naturally rich in folate, protein, dietary fibre, essential amino acids and minerals.

Researchers believe this enhanced plant-based approach contributed to improvements in several cardiometabolic health markers.

Higher folate levels linked to better health

The research was based on data from the DIRECT-PLUS randomised controlled trial, which examined whether a more plant-focused Mediterranean diet could provide greater health benefits than conventional dietary recommendations.

Compared with participants following a traditional Mediterranean diet or general healthy eating advice, those on the Green-MED diet had significantly higher blood folate concentrations.

Higher folate levels were associated with several measurable improvements, including:

  • Better insulin sensitivity.
  • Lower levels of the inflammatory marker interleukin-6 (IL-6).
  • Improved blood lipid profiles.
  • Reduced visceral fat surrounding internal organs.
  • Lower liver fat accumulation.

Folate, also known as vitamin B9, plays a crucial role in one-carbon metabolism, a biochemical process involved in DNA repair, cell growth and gene regulation through methylation.

Experts say efficient folate metabolism supports cardiovascular and metabolic health, while impaired folate processing has been linked to inflammation, elevated homocysteine levels and increased cardiovascular risk.

Diet may help overcome genetic limitations

Researchers paid particular attention to a common variation in the MTHFR gene, known as C677T (rs1801133).

Around 10% to 15% of people worldwide inherit two copies of the higher-risk version of this genetic variant, resulting in reduced activity of an enzyme responsible for processing folate efficiently.

Individuals with this genetic variation often have elevated homocysteine levels and face an increased risk of hypertension, heart disease, metabolic dysfunction-associated steatotic liver disease (MASLD), osteoporosis and certain age-related neurological conditions.

The study found that participants carrying this higher-risk genetic profile experienced lower cardiovascular risk scores when they closely followed the Green Mediterranean diet.

Researchers also observed increased activity in alternative folate-processing genes, including MTHFD2 and DHFR, suggesting that dietary changes may help compensate for reduced MTHFR enzyme activity.

These findings indicate that while genetic makeup cannot be altered, targeted dietary interventions may reduce some inherited health risks.

Mankai may play an important role

One distinctive feature of the Green Mediterranean diet used in the study was the inclusion of a daily mankai shake.

Participants carrying the higher-risk MTHFR genetic variant who consumed little mankai showed increased cardiovascular risk over time.

In contrast, those who consistently consumed the mankai-enriched Green-MED diet demonstrated substantially lower cardiovascular risk scores.

Although researchers cautioned that the study was not designed to isolate the effects of mankai alone, they believe the nutrient-rich aquatic plant may have contributed significantly to the overall health benefits observed.

Practical ways to follow the Green Mediterranean diet

Nutrition experts emphasise that the overall dietary pattern is more important than any single ingredient.

For individuals wishing to adopt a Green Mediterranean diet, experts recommend:

  • Eating more leafy green vegetables such as spinach, kale and fenugreek.
  • Including legumes like lentils, chickpeas, beans and peas regularly.
  • Choosing whole grains instead of refined cereals.
  • Consuming nuts, especially walnuts, in moderation.
  • Drinking green tea as part of a balanced diet.
  • Using olive oil as the primary cooking fat.
  • Reducing red meat and processed foods.
  • Increasing plant-based protein sources such as soy products and edamame.
  • Incorporating mankai into smoothies, soups or dips where available, while recognising that similar nutritional benefits can also be obtained from other folate-rich foods.

Dietitians noted that consistency, variety and long-term adherence remain the key factors for achieving health benefits.

More research still needed

While the findings are promising, researchers caution that the study cannot establish that folate or mankai alone caused the observed improvements.

Participants simultaneously adopted several dietary changes, making it difficult to identify which individual component produced the greatest effect.

In addition, gene activity was measured using blood samples, which may not fully represent changes occurring in other tissues of the body.

Scientists say further studies involving larger and more diverse populations are needed before firm clinical recommendations can be made.

Nevertheless, the research strengthens the growing body of evidence suggesting that nutrition can influence health beyond traditional metabolic pathways by modifying biological processes involved in gene regulation.

As the field of precision nutrition continues to evolve, studies such as this highlight the potential for personalised dietary strategies to improve long-term cardiovascular and metabolic health, even among individuals with inherited genetic vulnerabilities.