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Walnut-cholesterol study needed more scrutiny in CBS story



Walnuts have long been touted as a healthy, whole food, but new research just upped the homely nut’s reputation another notch.

In a study by researchers from the Hospital Clinic of Barcelona and Loma Linda University, more than 700 older, healthy adults were asked to add either a handful of walnuts to their daily diets or to follow their normal diet without eating nuts.

After one year, both groups experienced minimal body weight, triglyceride, and HDL cholesterol changes, but the walnut-eaters had significant reductions in LDL cholesterol (“bad” cholesterol) compared to the nut-free control group.

The research shows the well-known cholesterol-lowering effect of eating walnuts works equally well in the elderly, even in the long term, the authors reported at the Experimental Biology conference in San Diego.

“Given walnuts are a high-energy food, a prevailing concern has been that their long-term consumption might be associated with weight gain,” said study author Dr. Emilio Ros, director of the Lipid Clinic, Endocrinology & Nutrition Service at the Hospital Clinic of Barcelona, in a press statement. “”It’s encouraging to see that eating walnuts may benefit this particular population.”

Other walnut studies presented at the conference, funded in part by the California Walnut Commission, suggested the omega-3 fatty acid-rich nut may also benefit gut bacteria and help reduce inflammation.

Elisabetta Politi, nutrition director of the Duke Diet and Fitness Center at Duke University, said, “We advocate that people eat nuts, including walnuts, because they are high in healthy fat, low in carbohydrates and a good source of protein.”

Politi said a serving of walnuts is about 14 halves, which adds up to 180 calories. They’re rich in fiber, folic acid, and potassium. Walnuts are especially heart healthy because they have more polyunsaturated fat than almonds, cashews, peanuts, pecans, pistachios, and macadamia nuts per serving. Walnut oil can be a good alternative too, in dressings and for light basting, Politi said.

It’s still important to remember portion control, especially for people on weight loss programs, warned Politi.

“Try a serving in a snack bag. Eat walnuts mindfully,” she said.


3 Star


The homeliest nut just got better

Our Review Summary

walnutsThis story is about initial findings of a study abstract presented at the recent Experimental Biology conference in San Diego. The study looked at the effect of walnut consumption among older adults on cholesterol and other lipids.

On the plus side, the story made it clear that the research was funded by the California Walnut Commission. However, the story missed the mark in many other ways; chiefly, it didn’t provide any quantified results from the study, nor did the story make it clear that the study findings were initial, and not yet published in any journal. 


Why This Matters

Many Americans are struggling with heart disease, and diet plays an important part in this. Finding out if walnuts can help with heart health is a beneficial research endeavor. However, because groups like the California Walnut Commission are actively funding research, it’s important that journalists scrutinize the results, provide specifics on the data, and seek independent viewpoints on the research.


Does the story adequately discuss the costs of the intervention?

Not Applicable

Since this is a study of older adults–who are often on fixed incomes–an estimate of cost would have made the story stronger. But because walnuts aren’t notably expensive compared to other nuts, we’ll give this a pass.

Does the story adequately quantify the benefits of the treatment/test/product/procedure?

Not Satisfactory

There is no quantification in this story. The story says that the walnut eaters had reductions in bad cholesterol, but not how much. Is it even clinically significant? The story also says that neither group showed weight gain or changes in other cardiovascular markers, but nothing concrete is presented.  A mention of good gut effects of walnuts is totally without any supporting information.  About the only information actually given is that walnuts can be a fattening food and that portion control is necessary.

Does the story adequately explain/quantify the harms of the intervention?


The only harm mentioned is that walnuts can cause weight gain because they are high in calories. Because walnuts are a common food, there are no real expected harms except for those who are allergic to them.

Does the story seem to grasp the quality of the evidence?

Not Satisfactory

The story did not contain adequate details to help readers discern if this was a high-quality study or not. For example, how did they insure people actually ate the walnuts? One big red flag: These were findings presented at a conference–they haven’t been published in a peer-reviewed journal. Whenever that’s the case, journalists should be extra cautious, as it means other experts haven’t had a chance to review the work.

Does the story commit disease-mongering?


There is no disease mongering here. Weight gain with age is fairly common and maintaining cardiovascular health is important.

Does the story use independent sources and identify conflicts of interest?


Close call on this one, but we’re going with Satisfactory, since the story did identify that the walnut research was funded by the California Walnut Commission, and an independent nutrition expert was quoted–although she didn’t talk about the study. Ideally, an outside source could have provided commentary on the research, providing insight into the quality of the evidence.

Does the story compare the new approach with existing alternatives?

Not Satisfactory

There was no comparison of alternatives, either other nuts or foods or pharmaceuticals. This was a missed opportunity: If the article had explicitly stated the amount LDL was lowered in the intervention vs the control group, it might have compared other known interventions (statins, etc) that would achieve a similar effect.

Does the story establish the availability of the treatment/test/product/procedure?

Not Applicable

Walnuts are widely available everywhere, so this is not applicable.

Does the story establish the true novelty of the approach?

Not Satisfactory

There have been many studies done on nuts and their effects on cardiovascular health, but these past studies were not referenced. How does this study specifically add to the body of research? There’s an implied reference that this might be the first time cholesterol-lowering benefits were tested in older adults, but it’s not clear.

Does the story appear to rely solely or largely on a news release?


There is a news release that was obviously used in this story, but there was also an outside source, which is just enough to rate as Satisfactory.

Total Score: 4 of 8 Satisfactory


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