Fruit intake and reduced risk of hypertension: are there any forbidden fruits?

All major dietary guidelines and recommendations for the prevention of hypertension and cardiovascular disease strongly advocate for a diet high in fruit. TheWorld Health Organization (WHO) recommends a minimum daily intake of five servings of fruit and vegetables (400 g per day) to prevent non-communicable diseases. This was echoed by several other organisations such as the Centers for Disease Control (5-A-Day for Better Health) and the United Kingdom’s National Health Service (5 A Day campaign). However, the challenge to reach the five a day target was recently shown in the UK, where only 17% of hospital staff succeeded. These recommendations are based on a solid foundation of evidence from longitudinal and interventional studies indicating that a high intake of fruit is associated with a lower risk of hypertension and associated outcomes. When the Global Burden of Disease Study collaborators ranked 84 different metabolic, environmental and behavioural risk factors by risk-attributable disability adjusted life years (DALYs), a diet low in fruit was ranked 13th – climbing seven positions from being ranked 20th in 1990. The cardioprotective effects of fruit are wide-ranging and involve multiple beneficial effects due to a high content of fibre, minerals (potassium, magnesium), vitamins, phytochemicals (polyphenols and carotenoids), antioxidants and unidentified compounds which are likely to act synergistically to reduce cardiovascular risk. Despite fruits containing high concentrations of fructose, sucrose and glucose, epidemiological evidence suggests an anti-obesity effect of whole fruit intake – with many ascribing this to the high fibre content. Flowing from this argument, 100% fruit juices were targeted as culprits for the obesity epidemic in youth. Yet, a recent meta-analysis involving 34,470 individual children aged 1–18 years found fruit juice to be associated with a small amount of weight gain in those aged 1–6 years which was not clinically significant. They found no association of 100% fruit juice consumption with weight gain in children aged 7–18 years. This is supported by a study suggesting a greater intake of fruit in middle-aged and older women to be associated with a lower risk of becoming obese. Where large prospective cohorts in adults found no association between fruit juices and hypertension, a meta-analysis found fruit juice intake to be inversely associated with coronary heart disease, ischaemic stroke and all-cause mortality. Although there seems to be more clarity in terms of the pros and cons of fruit juice intake, the question remains unanswered as to whether all fruits were created equally. Is a general recommendation of 5-a-day appropriate for all fruit? There is a plethora of evidence on fruit consumption and cardioprotective benefits, but usually all fruits are grouped into a single category. Very few large-scale prospective studies have evaluated individual fruit intake and the risk of hypertension or cardiovascular disease. Making use of more than 20 years of prospective data from the Nurses’ Health Study I and II, and Health Professional Follow-up Study, Borgi et al. analysed individual fruits and incident hypertension. When including grapes/raisins, apples/pears, bananas, strawberries, blueberries, oranges, peaches/apricots/plums, prunes, avocoado and cantaloupe, the authors found a high intake of raisins/grapes and apples/pears to individually associate with reduced hypertension risk, whereas avocado and blueberries also associated with a significant trend towards lower hypertension risk. Cantaloupe intake was associated with an increased risk of hypertension. The beneficial results for apples and raisins replicated earlier findings from the more than 28,000 participants from the Women’s Health Study, which also indicated oranges – but not bananas, strawberries or blueberries – to be associated with a reduced risk of hypertension. In a systematic review and meta-analysis including 95 studies, Aune et al. also reviewed single