Fish Oil or Walnuts: Which Is Better to Lower Blood Cholesterol

For us who struggle with high blood cholesterol and triglicerides, here's an interesting study comparing the benefits of fish oil and walnuts, both sources of omega-3 fatty acids:

Which is better, walnuts or fish oil? Actually, the answer is both,
according to new research. In a clinical trial to compare the two types of
omega-3s, researchers at Loma Linda University in California found that
plant-derived omega-3 oil in walnuts offers different heart-health benefits than
the marine-derived omega-3 in salmon.

Their study, published recently in The American Journal of
Clinical Nutrition, found that the omega-3 fats in walnuts significantly lowered
total and LDL (bad) cholesterol more than the omega-3 fats in fatty fish,
whereas fish lowered triglyceride levels more than walnuts. Interestingly,
walnuts had no impact on triglyceride levels, compared with the control (no
walnuts or fish) diet, while fatty fish raised HDL (good) and LDL cholesterol. I
talked with the study’s lead author, Sujatha Rajaram, PhD, associate professor
of nutrition at Loma Linda, to learn more about the findings.

The researchers recruited 25 healthy men and women, aged 23 to 65, whose
heart lipid levels (cholesterol and triglycerides) were within normal range and
who agreed to eat only food prepared by the university for the entire study
period. Beginning with a one-week standard diet (30% total fat, 10% of which was
saturated fat), the study participants each went through three four-week cycles
of different diets -- a control diet with no fish or walnuts... a walnut diet
with the FDA-recommended amount of 1.5 ounces of walnuts a day but no marine
sources of omega-3... and a fish diet with a four-ounce serving of cooked salmon
twice a week but no walnuts nor any other plant source of omega-3. Blood samples
were drawn at the end of each four-week cycle.

Walnuts were chosen as the plant source of omega-3 fatty acids because the
FDA advises a daily intake of 1.5 ounces (about 14 whole walnuts) as part of a
low-fat, low-cholesterol, calorie-stable diet for people who want to reduce
their risk for heart disease. Salmon was chosen as the fish source because it is
seen as a particularly rich source of marine omega-3, and the American Heart
Association advises consumption of two servings of fatty fish per week for
prevention of heart disease. Note: The study was underwritten by the California
Walnut Growers Association.

The results, said Dr. Rajaram, are quite convincing. "We expected that
diets following current recommendations would offer good results -- but we were
amazed at the impact of those serving sizes." Here’s how it played
out...

Nuts decrease LDL: After four weeks of eating walnuts, the volunteers had a
noteworthy 9% drop in LDL compared with the control group. Every 1% decrease in
LDL results in a 2% decrease in risk for coronary heart disease, Dr. Rajaram
told me, noting that this means an overall reduction in heart disease risk of
18% for this group.

Fish decreases triglycerides: Four weeks of eating salmon brought an 11%
drop in triglycerides, which also lowers the risk for heart disease. The fish
diet also brought about a slight (4%) rise in both LDL (bad) and HDL (good)
cholesterol -- the rise in LDL while eating fish was more pronounced in those
whose blood cholesterol was already on the high side.

The real
take-home advice here is that there is no either/or when it comes to omega-3s.
For optimal heart health, you need to include both plant and marine sources in
your diet. Unfortunately, a number of fatty fish contain mercury and so do some
of the over-the-counter supplements made from them. Dr. Rajaram suggests that
those concerned about this consider taking microalgae-oil supplements and/or
using eggs enriched with omega-3, both of which may be helpful in meeting your
health needs.