Big studies give mixed news on fish oil, vitamin D

November 10, 2018 by Marilynn Marchione
Big studies give mixed news on fish oil, vitamin D
This undated photo provided by Amarin in November 2018 shows a capsule of the purified, prescription fish oil Vascepa. Although fish oil taken by healthy people, at a dose found in many supplements, showed no clear ability to lower heart or cancer risks, higher amounts of a purified, prescription fish oil, such as Vascepa, 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. (Amarin via AP)

Taking fish oil or vitamin D? Big studies give long-awaited answers on who does and does not benefit from these popular nutrients.

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 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 percent 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 percent of those on Vascepa had suffered one of these problems—a , stroke, heart-related death or clogged arteries requiring medical care—versus 22 percent of the others.

That worked out to a 25 percent 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—favorable odds, Stein said.

Side effects may be a concern: More people on Vascepa were hospitalized for an irregular heartbeat—3 percent versus 2 percent 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.

A BROADER TEST

The other study tested a lower 1 gram daily dose of a different type of fish oil—an EPA/DHA combo sold as Lovaza or Omacor and in generic form—in 26,000 people with no prior heart problems or cancer.

After about five years, rates of a combined measure of heart attacks, strokes and other problems were similar for fish oil users and a comparison group. Cancer rates and deaths also were similar.

Big studies give mixed news on fish oil, vitamin D
This undated photo provided by Amarin in November 2018 shows capsules and packaging for the purified, prescription fish oil Vascepa. Although fish oil taken by healthy people, at a dose found in many supplements, showed no clear ability to lower heart or cancer risks, higher amounts of a purified, prescription fish oil, such as Vascepa, 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. (Amarin via AP)

There were fewer heart attacks in the fish oil group—145 versus 200 in the comparison group. The study leader, Dr. JoAnn Manson at Brigham and Women's, called that "a substantial benefit," but several independent experts disagreed because of the way the study was set up to track this and certain other results.

"These findings are speculative and would need to be confirmed in a separate trial," said the Cleveland Clinic's Dr. Steven Nissen.

FISHY COMPARISONS?

Both studies share a problem: the oils used for the comparison groups, which may not have been true placebos. The Vascepa study used mineral oil, which interferes with statin drugs, raises cholesterol, and might have made the comparison group fare worse and made Vascepa look better than it truly was.

The other study used olive oil, which might have helped that comparison group do better, possibly masking any benefit to the others from fish oil.

Leaders of both studies say any effect from the comparison oils isn't enough to alter the main results, and independent experts agreed. But Nissen, who is leading another study, is using corn oil as a comparison.

THE 'SUNSHINE' VITAMIN

Manson's study also tested vitamin D, which the skin makes from sun exposure. It's tough to get enough from foods like milk, eggs and oily fish, though many foods now are fortified with it. Some studies have found that people with lower levels of D are more likely to develop cancer, but it's not known if supplements alter that risk.

Study participants took 2,000 international units of D-3 (the most active form of vitamin D, also called cholecalciferol) or fake vitamin pills for five years.

Vitamin D did not affect the odds of having a attack or stroke or developing cancer. After excluding the first two years of use, researchers saw fewer cancer deaths among those on the vitamin—112 versus 149 in the placebo group.

"Cancer can take years to develop" so a difference may not show up right away, Manson said. "This looks promising" and people will be studied longer to see if the trend holds up, she said.

Several other experts said these numbers just hint at a possible benefit that needs more study.

"These 'positive' results need to be interpreted with caution," Dr. Clifford Rosen of Maine Medical Center Research Institute and Dr. John Keaney Jr. of the University of Massachusetts wrote in a commentary in the medical journal.

Explore further: Aspirin disappoints for avoiding first heart attack, stroke

Related Stories

Aspirin disappoints for avoiding first heart attack, stroke

August 26, 2018
Taking a low-dose aspirin every day has long been known to cut the chances of another heart attack, stroke or other heart problem in people who already have had one, but the risks don't outweigh the benefits for most other ...

Aspirin disappoints for avoiding first heart attack, stroke

August 27, 2018
Taking a low-dose aspirin every day has long been known to cut the chances of another heart attack, stroke or other heart problem in people who already have had one, but the risks don't outweigh the benefits for most other ...

Fish oils do not prevent heart attack or strokes in people with diabetes

August 26, 2018
Fish oil supplements do not prevent heart attacks or strokes in patients with diabetes, according to late breaking results from the ASCEND trial presented today in a Hot Line Session at ESC Congress 2018 and published in ...

Study: Fish oil's work vs. heart attacks limited

May 8, 2013
Eating fish is good for your heart, but taking fish oil capsules does not help people at high risk of heart problems who are already taking medicines to prevent them, a large study in Italy found.

Fish oil supplements may not help your heart: study

February 2, 2018
(HealthDay)—Claims that fish oil supplements help prevent death from heart disease, heart attacks and stroke may be unfounded, British research suggests.

Recommended for you

Teens get more sleep with later school start time, researchers find

December 12, 2018
When Seattle Public Schools announced that it would reorganize school start times across the district for the fall of 2016, the massive undertaking took more than a year to deploy. Elementary schools started earlier, while ...

Higher risk of heart attack on Christmas Eve

December 12, 2018
The risk of heart attack peaks at around 10pm on Christmas Eve, particularly for older and sicker people, most likely due to heightened emotional stress, finds a Swedish study in this week's Christmas issue of The BMJ.

Large restaurant portions a global problem, study finds

December 12, 2018
A new multi-country study finds that large, high-calorie portion sizes in fast food and full service restaurants is not a problem unique to the United States. An international team of researchers found that 94 percent of ...

Your weight history may predict your heart failure risk

December 12, 2018
In a medical records analysis of information gathered on more than 6,000 people, Johns Hopkins Medicine researchers conclude that simply asking older adult patients about their weight history at ages 20 and 40 could provide ...

Age is the biggest risk for heart disease, but lifestyle and meds have impact

December 12, 2018
Of all the risk factors for heart disease, age is the strongest predictor of potential trouble.

New understanding of mysterious 'hereditary swelling'

December 12, 2018
For the first time ever, biomedical researchers from Aarhus University, Denmark, report cellular defects that lead to a rare disease, hereditary angioedema (HAE), in which patients experience recurrent episodes of swelling ...

6 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

szore88
3.4 / 5 (5) Nov 10, 2018
You need to get these nutrients from natural whole foods, it's the only way your body will absorb it.
billpress11
5 / 5 (3) Nov 11, 2018
I notice some contradictions in the article. And to make a comparison between a highly refined fish oil with a highly refined crude oil product has to be a cruel joke.

It appears to me to be just another attempt by a big drug company to foist another expensive drug of dubious value on an already over medicated America.
Jim4321
not rated yet Nov 11, 2018
Fish oil goes bad easily. Supplements have been chemically modified to prevent oxidation. But if it is stabilized then it will be harder to absorb and digest. This and related articles would be much more informative if they discussed this problem and how they got around it.

The negative tone of this article is unwarranted. Despite the large number of participants, the small number having cardiovascular events make the statistics challenging. There were many promising secondary end points that need to be checked out -- the only one the author mentioned was cancer. This was a slip-up by the investigators -- the latency period should have been included in the design of the trial.

This is not the end -- it is the beginning.
SuzieQue
5 / 5 (2) Nov 11, 2018
The body can't utilize calcium without Vitamin D. If your calcium gets low, your blood pressure goes up because of the calcium-sodium imbalance. This is a long term effect. Good nutrition is fundamental to good health. Good nutrition includes adequate intake of Vitamin D.
Ojorf
1 / 5 (1) Nov 11, 2018
But SusieQue, this is just another in a long list of studies that show vitamins/supplements have no benefit in healthy individuals.
It is easy to give someone a supplement and analyze their urine to determine how much was absorbed. People who take vitamins/supplements every day literally piss it all away.
Telekinetic
not rated yet Nov 12, 2018
This article is a thinly veiled advertisement for the pharmaceutical company that makes Vascepa. I wouldn't be surprised if there was monetary compensation made to this site and/or author of this despicable crap.
Remember that the pharmaceuticals Vioxx and Celebrex were responsible for the unnecessary deaths of at least 70,000 people which resulted in numerous wrongful death class action lawsuits. That is the vile reality and tragedy for so many people who obey their M.D.'s and never question their worsening condition. Natural fish oils, not this overly processed chemical, have been used to great advantage and effect by populations for centuries! I take 5,000 i.u.'s of Vitamin D everyday and have suffered no colds, flu, or serious illness. I attribute my robust health to my vitamin supplementation and avoiding anything made by these purveyors of death.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.