Big studies give long-awaited answers on who does and does not benefit from these popular nutrients.

Axar.az reports that fish oil taken by healthy people, at a dose found in many supplements, showed no clear ability to lower heart or cancer risks. Same for vitamin D.

But higher amounts of a purified, prescription fish oil slashed heart problems and heart-related deaths among people with high triglycerides, a type of fat in the blood, and other risks for heart disease. Doctors cheered the results and said they could suggest a new treatment option for hundreds of thousands of patients like these.

Up to 10 per cent of U.S. adults take fish oil. Even more take vitamin D, despite no major studies to support the many health claims made for it.

“Those who peddle it promote it as good for everything,” but in this definitive test, vitamin D “showed a big nothing,” said Dr James Stein, a heart specialist at the University of Wisconsin-Madison. He had no role in the studies or ties to the companies involved.

Results were revealed Saturday at an American Heart Association conference in Chicago and published by the New England Journal of Medicine.

ABOUT FISH OIL

These oils, also called omega-3 fatty acids, are found in salmon, tuna and certain other fish. They reduce triglycerides and inflammation and may have other effects. There are different types, including EPA and DHA.

One study tested 4 grams a day of Amarin Corp.’s prescription Vascepa, which is concentrated EPA, in more than 8,000 patients with high triglycerides and a greater risk of heart problems for various reasons. All were already taking a statin such as Lipitor or Zocor to lower cholesterol. Half were given Vascepa and the rest, mineral oil capsules as a comparison.

After five years, about 17 per cent of those on Vascepa had suffered one of these problems — a heart attack, stroke, heart-related death or clogged arteries requiring medical care — versus 22 per cent of the others.

That worked out to a 25 per cent reduction in risk. Looked at individually, heart attacks, heart-related deaths and strokes all were lower with Vascepa. Only 21 people would need to take Vascepa for five years to prevent one of the main problems studied — favourable odds, Stein said.

Side effects may be a concern: More people on Vascepa were hospitalized for an irregular heartbeat — 3 per cent versus 2 per cent of the comparison group. Doctors say that’s puzzling because other research suggests fish oil lowers that risk.

The concern with the heart rhythm problem is that it can raise the risk of stroke, but there were fewer strokes among those on Vascepa, said study leader Dr Deepak Bhatt of Brigham and Women’s Hospital in Boston.

Vascepa costs around $280 a month; many insurers cover it. Amarin sponsored the study and some study leaders work or consult for the company.