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Approved Research

Exploring the benefits of foods rich in high molecular weight polyphenols on non-alcoholic fatty liver disease incidence and cardiometabolic comorbidities, gut health and cognitive function.

Principal Investigator: Dr Peter Curtis
Approved Research ID: 77861
Approval date: September 14th 2022

Lay summary

We aim to find out if eating natural compounds called 'tannins', found in large amounts in particular fruits, nuts, beans & pulses and the products made from them (like apples, pears, cocoa, berries, some nuts, broad beans, red wine, dark chocolate), are linked to better health. The tannins in these foods are very large, and have complex chemical structures (made up of lots of smaller units joined together), which the body finds difficult to break down. As these large structures travel through the stomach and small intestine, they interfere with how sugars and fats are processed by the body, which lowers their availability. This inhibition is one of the ways that tannins reduce hyperglycaemia (i.e. elevated blood sugar) and hypercholesterolaemia (i.e. elevated cholesterol) after eating. The majority of the tannins in these foods reach the large intestine, and are fermented by gut microbes into bi-products that are thought to have health benefits - both in the immediate gut environment, and also throughout the body (i.e. blood vessels, liver, energy storage tissues, muscles, brain). 

To date, evidence suggests that eating tannins protects against heart disease and diabetes. Controlled studies have also shown that eating particular tannin-rich foods can improve; how blood vessels are controlled, how the body processes fat and sugar, how hunger and bodyweight are regulated, and how the brain responds to performance tests. Yet, despite numerous animal studies showing that tannins lower liver fat levels and reduce liver damage, there are no human cohort data (similar to the BIOBANK cohort) which have assessed the relationship between tannin rich food intake and liver health.

Over a 3-year period, we will address this research gap using the BIOBANK UK cohort; comparing the intake of tannin-rich foods against liver fat and liver inflammation levels. We will also establish if the intake of particular tannin rich foods, or groups of foods (e.g. fruits, nuts, beans and pulses), are associated with health markers linked to liver health; such as inflammation, heart health, body size, blood glucose control and blood fat levels, and cognition. We will also control for characteristics that might affect health, like menopause status / HRT use, and assess whether genetic differences alter the relationship between tannin intake and cardiometabolic and liver health outcomes. 

A successful project will provide new knowledge of whether plant-based foods promote liver, brain and heart-health and may facilitate health management strategies in those at risk.