Increasing key foods, and cutting two, as good as extra 4,000 steps

Eating plenty of fruit, veg and whole grains is as good for older people as taking more than 4,000 extra steps a day, according to research. The findings sow it boosts organ systems - including those of the heart, lungs, blood vessels and muscles.

Cardiorespiratory fitness reflects the body’s ability to provide and use oxygen for exercise, say scientists. Lead author Dr Michael Mi, of Beth Israel Deaconess Medical Centre in the US, said: "This study provides some of the strongest and most rigorous data thus far to support the connection that better diets may lead to higher fitness.

"The improvement in fitness we observed in participants with better diets was similar to the effect of taking 4,000 more steps each day."

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Healthy diets are known to reduce risk of heart disease and cancer - the world's two biggest killers. Among people who do the same amount of physical activity there are differences in fitness - suggesting additional factors are involved.

The study of 2,380 middle aged American men and women identified nutrition as key. Participants completed a food frequency questionnaire to assess consumption of 126 items during the last year ranging from never or less than once per month to six or more servings per day.

The information was used to rate diet quality using the Alternative Healthy Eating Index (AHEI; 0 to 110) and Mediterranean-style Diet Score (MDS; 0 to 25), which are both associated with heart health. Higher scores indicated a better quality diet emphasising vegetables, fruits, whole grains, nuts, legumes, fish and healthy fats and limiting red meat and alcohol.

Dr Mi said: “In middle-aged adults, healthy dietary patterns were strongly and favourably associated with fitness even after taking habitual activity levels into account. The relationship was similar in women and men, and more pronounced in those under 54 years of age compared to older adults."

Further analysis identified 24 metabolites - substances produced during digestion and released into the blood during exercise - that were linked to either poor or favourable diet and fitness. Dr Mi said: "Our metabolite data suggest eating healthily is associated with better metabolic health, which could be one possible way that it leads to improved fitness and ability to exercise."

The US team took into account age, sex, total daily energy intake, BMI (body mass index), smoking status, cholesterol levels, blood pressure, diabetes and routine physical activity level. The average AHEI and MDS were 66.7 and 12.4, respectively. Compared with the average score, an increase of 13 points on the AHEI and 4.7 on the MDS was associated with a 5.2% and 4.5% greater 'peak VO2' - the maximum amount of oxygen your body can utilise during exercise - respectively.

Dr Mi added: "This was an observational study and we cannot conclude that eating well causes better fitness, or exclude the possibility of a reverse relationship, i.e. that fit individuals choose to eat healthily. There are already many compelling health reasons to consume a high-quality diet, and we provide yet another one with its association with fitness. A Mediterranean-style diet with fresh, whole foods and minimal processed foods, red meat and alcohol is a great place to start."

The study was published in the European Journal of Preventive Cardiology.