Eating grapes decreases cholesterol levels which may help prevent heart attacks and strokes, a new study suggests.
Researchers in California gave participants 46 grams per day of whole grape powder, providing the equivalent of two servings of California table grapes.
Consuming grapes significantly increased the diversity of bacteria in the gut, which is considered essential to a strong immune system, the experts found.
Additionally, eating grapes significantly decreased levels of cholesterol, the fat-like substance in our blood that can clog up the arteries and lead to heart diseases.
Eating grapes was also found to reduce levels of bile acids, which play an integral role in metabolising, or processing, cholesterol.
It has long been known that grapes and other fruits like apples contains antioxidants called polyphenols – organic compounds naturally present in plants – which keep blood vessels healthy and flexible for good circulation.
Polyphenols and other ‘phytochemicals’ can also reduce and help control blood sugar levels and blood pressure levels, and reduce chronic inflammation, another risk factor for heart disease.
Grape consumption benefits gut microbiome and cholesterol metabolism, researchers in California report (stock image)
Grapes and other fruits like apples contains antioxidants called polyphenols. These organic compounds are naturally present in plants.
They’re known keep blood vessels healthy and flexible for good circulation.
There are more than 8,000 types of polyphenols, including stilbenes in vegetables and resveratrol in red wine.
Polyphenols are phytochemicals – compounds found largely in fruits, vegetables, tea, coffee, chocolates, legumes, cereals, and beverages.
The new study was led by Zhaoping Li, a nutritionist and professor of medicine at the University of California, Los Angeles, and published in the journal Nutrients.
‘We found that grapes have a beneficial effect on gut bacteria, which is great news, since a healthy gut is critical to good health,’ said Professor Li.
‘This study deepens our knowledge and expands the range of health benefits for grapes, even as the study reinforces the heart health benefits of grapes with lowered cholesterol.’
For the study, the experts analysed the microbiota – the trillion-strong community of microorganisms – of centenarians based on their stool samples.
Microbiota is also known as the microbiome – although this latter term includes the collective genomes of the microorganisms in a particular environment, as well as the microorganisms themselves.
In total, 19 healthy subjects consumed a low-polyphenol and low-fibre diet for four weeks.
For another four weeks, they were given 46 grams of grape powder per day for four weeks, while continuing to consume the low-fibre and low-polyphenol diet.
Stool and urine samples were collected before and at the end of the grape powder supplementation period.
Cardiovascular disease (CVD) is a general term for conditions affecting the heart or blood vessels. CVD events include heart disease and stroke. All heart diseases are cardiovascular diseases, but not all cardiovascular diseases are heart disease (stock image)
After four weeks of grape consumption there was an increase in microbial diversity as measured by the Shannon index, a commonly used tool for measuring diversity of species.
Among the beneficial bacteria that increased was Akkermansia, a bacteria of keen interest for its beneficial effect on glucose and lipid metabolism, as well as on the integrity of the intestinal lining.
Additionally, a decrease in blood cholesterol was observed including total cholesterol by 6.1 per cent and LDL (low-density lipoprotein) cholesterol by 5.9 per cent.
Bile acids – steroid acids which are linked to cholesterol metabolism – decreased by 40.9 per cent, they found.
The findings suggest a promising new role for grapes in gut health and reinforce the benefits of grapes on heart health, according to the team.
Previous research has already suggested a link between consuming grapes in many forms, including red wine, and heart benefits.
Grapes in various forms, including powders and red wine (pictured) has already been linked to improved heart heath (stock image)
Earlier this year, researchers in Germany and Northern Ireland found three 125ml glasses of red wine per week lowered blood pressure.
According to the team, another type of phytochemical called flavonoids – the abundant nutrients in fruits, vegetables, tea and other plant-based foods – appear to have a positive effect on blood pressure levels.
Flavonoids are broken down by the trillion-strong community of microorganisms in our gut, known as the microbiota.
Back in 2010, University of Michigan researchers studied the effect of regular table grapes (a blend of green, red and black grapes) mixed into a powdered form and integrated into the diets of lab rats as part of a high-fat, American style diet.
After three months, the rats that received the grape-enriched diet had lower blood pressure, better heart function, and reduced indicators of inflammation in the heart and the blood than rats who received no grape powder.
CHEMICALS IN APPLES BOOST BRAIN FUNCTION AND REDUCE YOUR RISK OF ALZHEIMER’S DISEASE, SCIENTISTS SAY
Natural compounds found in apples can reduce the risk of developing Alzheimer’s and other forms of dementia, scientists reported in 2021.
High concentrations of compounds in apples and other plants, known as ‘phytochemicals’ or ‘phytonutrients’, stimulate the creation of neurons, in a process called neurogenesis.
Neurons are highly excitable cell that transmits information to parts of the body via electrical signals – and they boost our learning and memory abilities.
Two compounds – quercetin in apple peel and dihydroxybezoic acid (DHBA) in apple flesh – generated neurons in the brains of mice in lab tests.
Interestingly, apple juice was not found to significantly contribute to neurogenesis, suggesting the benefits apply to eating the whole apple and not just a glass of juice.
Read more: An apple a day can reduce Alzheimer’s risk, scientists say