The following article is based on a transcript of a video called “True Health Facts of Walnuts: Examining the Evidence.” Watch the complete video to access any visual materials.
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A comprehensive review included only randomized controlled trials, also known as RCTs. RCTs are considered one of the more reliable methods for measuring any causal effects. Unfortunately, the researchers noticed that the study designs weren’t always of high quality.
Despite that, they found that the evidence was significant regarding the ability of walnuts to lower LDL and triglycerides, both risk factors for heart disease. However, this review did not manage to escape the problem we sought to evade. More than half of the studies were funded by the walnut industry, potentially affecting the results as it is more likely to happen among industry-funded studies.
That said, if we’d disregard those studies, we’d still end up with more or less the same results.
One interesting study found that by enriching steaks with 20 (o.7 oz) grams of walnuts, participants were able to lower their LDL by 5% versus eating regular steak.
When the steak group switched over to the walnut-enriched steak, LDL went down, and when the walnut group started eating regular steak, LDL went up. LDL still is, and always has been, a strong causal factor for heart disease.
The higher the LDL, the higher the risk. The lower the LDL, the lower the risk.
Despite these findings, confusion persists, even among health professionals, particularly on social media.
What’s the conclusion we can draw?
The true health benefits of walnuts for health
The strongest evidence supports the health benefits of walnuts in lowering blood lipids and therefore improving heart health. The most objective analysis of LDL I have come across is discussed in several videos on the YouTube channel Nutrition Made Simple.
That makes sense because walnuts are the richest source of antioxidants in the nut kingdom and are rich in the omega-3 fatty acid ALA.
Although there is some evidence that walnuts have positive effects on other areas, like brain function, we need more higher-quality studies to confirm that.
All in all, walnuts still appear to be a healthy choice.
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Keep track of all your nutrients in the best free online nutrition calculator: Cronometer
How many walnuts a day?
From the main review I mentioned earlier that analyzed all the different trials and meta-analyses, the ideal quantity of walnuts remains unclear. However, based on the available evidence we can come to an estimated range. Walnuts serving size is about 14 grams (o.5 oz). Most of the benefits from the studies have come after consuming a daily amount of 20 or more grams (o.7 oz +). The FDA recommends 1.5 oz, or 42 grams of walnuts daily.
In more practical terms, you could just aim for a handful of unshelled walnuts.
Other food sources that are even higher in omega 3, are flax seeds and chia seeds.
Though (any of) these three are good to eat daily, it’s perfectly fine to eat a variation of nuts and seeds. Remember that nuts and seeds fit in a well-balanced diet plan, whether that’s a diet plan focused on mostly plant foods that I recommend or otherwise.