Rainbow Diet

Major health benefits of walnut consumption

Walnuts are an important part of the Mediterranean diet and have been shown to improve heart health, lower ‘bad’ cholesterol and blood pressure, improve mental function and even alter the DNA in cancer patients.

Not all nuts were created equal. Walnuts are bundles of health. Consuming just 7 walnuts provides 2 gm of fibre and 4 gm of protein along with a variety of vitamins, minerals and enzymes.

Walnuts lower cholesterol and benefit heart health

Walnuts, in particular, are known to contain much higher levels of polyunsaturated fatty acids – the healthy fats of the Rainbow Diet. They also contain alpha-linolenic acid and linoleic acid, known to protects blood vessels and keeping them in a healthy state. These health benefits have been shown in research.

In a 2018 meta-analysis of 26 studies involving 1059 participants, those on walnut-enriched diets had lowered total cholesterol (-6.9 mg/dL), lowered ‘bad’ LDL cholesterol (-5.5 mg/dL), lower apoprotein B, which leads to heart disease, (3.9 mg/dL) and lowered triglycerides (-4.69 mg/dL). The effects were more marked where the controls were those of the standard Western or American diets.

In this analysis, walnut-enriched diets did not lead to significant benefits in weight loss, or blood pressure (systolic or diastolic). In 2019, however, a study in the Journal of the American Heart Association (2) showed that eating whole walnuts reduced bad cholesterol and diastolic blood pressure.

Walnuts alter gene expression

Walnut consumption seems beneficial to cancer patients too and leads to increased survival times. In a series of studies with breast cancer patients by Marshall University, walnut consumption suppressed cancer growth, increasing survival and was even shown to modify gene expression for the better. Just two handsful of walnuts sufficed.

In a seven year study by the Dana-Faber Institute with Colorectal cancer patients, just a 2 ounce addition of walnuts per day resulted in a 57 per cent lowered risk of dying and a 42 per cent lowered risk of recurrence (3).

Walnuts linked to slower cognitive decline

In the ‘Walnuts and healthy ageing study’ published in 2020 (4), consuming 15 per cent of your calories by eating walnuts showed significant improvement in the brain MRIs of ‘at-risk’ people (for example, smokers, or people with lower Neuro-physiological scores.

Go to: How fibre ‘works’ in the Mediterranean Diet


  1. Effects of walnut consumption on blood lipids; The American Journal of Clinical Nutrition, Volume 108, Issue 1, July 2018, Pages 174–187, https://doi.org/10.1093/ajcn/nqy091
  2. Walnut consumption improves blood pressure
  3. Walnut consumption improves cancer survival
  4. WAHA Study. The American Journal of Clinical Nutrition, Volume 111, Issue 3, March 2020, Pages 590–600, https://doi.org/10.1093/ajcn/nqz328

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