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A recent study made media headlines questioning whether eating veggies really protected your heart. Since eating ‘lots of veggies’ has been the mainstream nutrition recommendation for promoting health and wellness, we thought a closer look into this new research was warranted. Here we bring you the Dietitians’ translation of the science into meaningful advice to support healthy living.
The Study [1]
Published in the Frontiers of Nutrition, a new study by researchers from the University of Oxford, the University of Hong Kong, and the University of Bristol involved nearly 400 000 British adults and 12 years of follow up. There are strengths in the diverse team and sample size. The study initially found that the people who consumed the highest amount of vegetables had a 10% lower incidence of cardiovascular disease compared to the people with the lowest vegetable intakes. However, when they adjusted for socioeconomic and lifestyle factors (including physical activity, body weight, high blood pressure, smoking and other nutrients) any protective effect of vegetable intake became much less important. [2] This surprising finding resulted in the headlines ‘Eating vegetables may not protect against heart disease.’
Low quality evidence
- Very low vegetable intakes
The study says the “Mean intakes of raw and cooked vegetables were 2.3 and 2.8 tablespoons/day, respectively”. This amount is very low, less than half a serving per day! Healthy dietary guidelines recommend much more than this. For example, the WHO suggests consuming at least 400 g (i.e., five portions) of fruit and vegetables per day excluding potatoes, sweet potatoes, cassava and other starchy roots to improve overall health and reduce the risk of cardiovascular disease. [3] - Observational study errors
One of the limitations of this observational study was that all data was self reported and vegetable intakes may not have been reported accurately, causing measurement errors. It is possible that the study participants had difficulty visualizing their vegetable intakes as their number of “heaping tablespoons”, which the questionnaire asked them to estimate for their vegetable intakes.1 - Inconsistent with current evidence
This is one surprising study whose findings are not supported by the significant amount of existing data. Current mainstream evidence shows higher vegetable consumption promotes health and reduces the risk of cardiovascular disease.
Our Recommendations
Keep eating plenty of vegetables and fruit for health including your heart health! Make veggies and fruit half your plate at each meal. Pile your plate with colour and eat at least one dark green and one orange vegetable each day.
Do you have a food or nutrition question? Ask us! Registered Dietitians look beyond fads to deliver reliable, life-changing advice.
Written by Lucia Weiler, BSc, RD, PHEc, Award-winning dietitian and Co-Founder, n4nn
[1] Feng Q, Kim JH, Omiyale, Bešević j, Conroy M, May M, et al. Raw and cooked vegetable consumption and risk of cardiovascular disease: a study of 400,000 adults in UK biobank. Front Nutr. 2022 Feb; 9:831470. doi: 10.3389/fnut.2022.831470. Available at: https://www.frontiersin.org/articles/10.3389/fnut.2022.831470/full
[2] Dietitians of Canada, PEN Nutrition (2022) Available at: https://www.pennutrition.com/TrendingTopic.aspx?id=29382 (PEN registration required to access)
[3] Diet, nutrition and the prevention of chronic diseases: report of a Joint WHO/FAO Expert Consultation. WHO Technical Report Series, No. 916. Geneva: World Health Organization; 2003. Available at: WHO_TRS_916.pdf
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