A VITAMIN used to lower cholesterol may have a paradoxical side effect of increasing the risk of heart disease, a study has found.
Niacin, also known as vitamin B3, is essential for various bodily functions and is sometimes added to fortified foods.
However, researchers at the Cleveland Clinic have now found that surplus niacin increases the circulation of a by-product called 4PY.
Higher circulating levels of 4PY have been linked to heart attack, stroke and other adverse cardiac events in large-scale clinical studies.
The researchers also showed it directly triggers inflammation to blood vessels.
Niacin used to be prescribed to increase HDL cholesterol — the “good” cholesterol that helps remove LDL, the “bad” cholesterol, from the bloodstream.
However, eventually, niacin was shown to be less effective than other cholesterol-lowering drugs.
Dr Stanley Hazen, who led the research, says: “For decades, the United States and more than 50 nations have mandated niacin fortification in staple foods such as flour, cereals and oats to prevent disease related to nutritional deficiency.
“Given these findings, a discussion over whether a continued mandate of flour and cereal fortification with niacin in the US could be warranted.”
Meanwhile, over-the-counter supplements made with forms of niacin claim to be anti-ageing, improve blood fats, skin health, brain function and more.
They can be bought for as little as 3p per pill online and in health food stores.
The study, published in Nature Medicine, found one in four subjects in the researchers’ patient cohorts had high levels of 4PY, which suggested they had too much intake of niacin.
Dr Hazen says: “Niacin’s effects have always been somewhat of a paradox.
“Despite niacin lowering of cholesterol, the clinical benefits have always been less than anticipated based on the degree of LDL reduction.
“This led to the idea that excess niacin caused unclear adverse effects that partially counteracted the benefits of LDL lowering.
“We believe our findings help explain this paradox. This illustrates why investigating residual cardiovascular risk is so critical; we learn so much more than what we set out to find.”
The NHS says most people get enough niacin from their daily diet, with good sources including meat, fish, eggs and wheat flour.
There are two forms of niacin: nicotinic acid and nicotinamide.
The NHS says: “Taking high doses of nicotinic acid supplements can cause skin flushes. Taking high doses for a long time could lead to liver damage.
“There’s not enough evidence to know what the effects might be of taking high daily doses of nicotinamide supplements.”
It therefore recommends limiting doses to 17mg of nicotinic acid or 500mg of nicotinamide per day.
There are a number of ways to reduce your cholesterol.
High levels of cholesterol can build up in the artery walls and reduce blood flow to the heart.
This increases the risk of a clot forming around the body and also coronary heart disease occurring.
According to the NHS website, high levels can lead to:
High cholesterol is mainly caused by eating fatty food, not exercising enough, being overweight, smoking and drinking alcohol. Therefore, to lower your cholesterol:
