Omega-3 may help those at risk of heart problems

Dear Dr. Roach: Are there any benefits to taking omega-3?

B.H.

Yes, there are, but it’s not clear just how big those benefits are.

Although there has been some evidence that omega-3 fatty acids may be of benefit in slowing dementia, treating depression and helping with asthma symptoms, the consensus is that omega-3 supplements are unlikely to have a large benefit when it comes to these health areas.

However, most of the interest in omega-3 fatty acids is in cardiovascular health.

There have been many studies looking at the effect of fish-derived omega-3 fatty acids on a variety of heart outcomes.

Certainly, they reduce triglycerides and slightly increase HDL levels.

They slightly reduce blood pressure and reduce heart rate.

Like other cholesterol-lowering agents, such as niacin and statins, they slightly increase blood-sugar levels, though to a lesser extent than other agents.

In large clinical trials looking at the outcomes that matter, such as heart attack and overall risk of dying, the study results are mixed.

Earlier studies tend to show a large benefit, while more recent studies show a small benefit.

However, no studies have suggested significant harm, and my view after reviewing the available studies is that omega-3 supplementation is likely to have a modest heart benefit.

The greater the risk of heart disease for a given individual, the more benefit he or she is likely to get.

The amount of omega-3 needed to benefit is small, about 250 mg per day of EPA plus DHA (the two different forms).

This can be obtained by a supplement, or by eating about two servings of fatty fish per week.

Dear Dr. Roach: What is a tilt table test for?

J.C.

The tilt table test is most commonly ordered to determine the cause of syncope, a sudden loss of consciousness.

Most cases of syncope are caused by a simple faint (called vasovagal syncope), and can be reliably diagnosed as such by an experienced clinician after a careful history and physical exam.

In people with a history of syncope and with risk factors for coronary artery disease — blockages in the blood vessels of the heart that can lead to heart attack — it is important to evaluate for heart blockages with a stress test or angiogram.

If coronary disease has been ruled out, and if the syncope is recurrent, then a tilt table test may be ordered.

It is sometimes used to distinguish between convulsive syncope (fainting associated with muscle spasm) and epilepsy.

As its name implies, the tilt table is capable of moving a patient rapidly between lying down and upright while monitoring symptoms, the EKG and blood pressure.

Sometimes medication is used to improve the sensitivity of the test; however, the test is neither 100 per cent sensitive nor specific.

As a general internist, I seldom order this test and refer unexplained cases of recurrent syncope to a cardiologist.

Dear Dr. Roach: I’m curious about the preservative BHT. I don’t believe I’ve ever seen this addressed in your column.

I try to eat as natural as possible, but I do have cold cereal sometimes in the morning.

Almost all boxes have the preservative BHT. Should I be concerned?

J.W. Butylated hydroxytoluene (BHT) is a commonly used antioxidant preservative used in foods and cosmetics.

The safety has been extensively studied, but there remain conflicting reports, as some studies show an increase and others a reduction in cancer risk in animals.

It is also sold as a nutritional supplement.

At the extremely low doses used as a food preservative, the consensus of most scientists, including the Food and Drug Administration, is that it has very low risk.