Long-term study shows vegetables and fruit are the key to long life

1 April 2014

A study looking at eating habits and mortality in a large population sample in England has shown that the more vegetables and fruit you eat the longer you live.

Eating at least seven daily portions of fruit and vegetables may confer the best chance of avoiding death from any cause, and vegetables may be more protective than fruit. The study was published online in the Journal of Epidemiology and Community Health [1].

This study follows a wider European study into cancer and nutrition published last year that also found eating over 500gms vegetables a day was the most beneficial to health, especially raw vegetables, which reduced risk of death by 16% [2].

In the UK study, the researchers analysed lifestyle data for more than 65,000 randomly selected adults aged at least 35, derived from annual national health surveys for England between 2001and 2008. They also tracked recorded deaths from among the sample for an average of 7.5 years.

On average, the survey respondents said they had eaten just under four portions of fruit and vegetables the previous day. During the monitoring period 4399 people died (6.7% of the sample).

The analysis revealed that eating fruit and vegetables was associated with a lower risk of death, overall, and deaths from heart disease/stroke and cancer. The higher the intake of fruit and vegetables, the greater the protective effects seemed to be.

Eating at least seven daily portions was linked to a 42% lower risk of death from all causes and from cancer and heart disease/stroke of 25% and 31%, respectively, after excluding deaths within the first year of the monitoring period.

Vegetables may be more protective, the figures suggest: 2-3 daily portions were linked to a 19% lower risk of death, compared with a 10% lower risk for the equivalent amount of fruit. And each portion of salad or vegetables seemed to confer a 12-15% lower risk of death.

But while fresh and dried fruit seemed to strongly curb the risk of death, a portion of frozen/tinned fruit seemed to increase it by 17%, which public health doctors from the University of Liverpool describe in an accompanying editorial as “intriguing”. They speculate that this could be due to the sugar content.

They conclude that current dietary guidance, which includes consumption of dried or tinned fruit, smoothies, and fruit juice as legitimate ways of reaching the ‘5-a-day’ goal, might need to be revised.

“150 ml of freshly squeezed orange juice (sugar 13 g); 30 g of dried figs (sugar 14 g); 200 ml of a smoothie made with fruit and fruit juice (sugar 23 g) and 80 g of tinned fruit salad in fruit juice (sugar 10 g)...contain a total of some 60 g of refined sugar,” they point out. “This is more than the sugar in a 500 ml bottle of cola.”

As only one in four adults in England gets their recommended ‘5 a day’ the health benefits of getting everyone else to up their game are “huge,” they suggest.

But the study findings imply that even those who do get their recommended quota, need to eat more, they say. “Is it perhaps now time for the UK to update the ‘5 a day’ message to ‘10 a day’? they ask.

See below for original research paper.

The European study

This study, published in 2013, was directed by researchers from ten countries, as part of the European Prospective Investigation into Cancer and Nutrition (EPIC). It was published in the American Journal of Epidemiology [2].

The sample analyzed includes 25,682 deaths (10,438 due to cancer and 5,125 due to cardiovascular disease) among the 451,151 participants studied over more than 13 years.

According to the results, a combined fruit and vegetable consumption of more than 569 grams per day reduces the risk of mortality by 10% and delays the risk of mortality by 1.12 years compared to a consumption of less than 249 grams per day.

Furthermore, for every 200 gram increase in daily fruit and vegetable consumption, the risk falls by 6%. The proportion of deaths that could be prevented if everyone eating too few fruit and vegetables increased their consumption by 100-200 grams per day — thus reaching the recommended 400-500 grams per day — is 2.9%.

Previous studies already noted that fruit and vegetable consumption, in accordance with the recommended daily allowance, prevents the development of chronic diseases, and reduces the risk of mortality by 10-25%.

"This study is the most significant epidemiological study that this association has examined to date," María José Sánchez Pérez, director of the Andalusian School of Public Health's (EASP) Granada Cancer Registry and one of the authors of the research, explains to SINC.

There is now sufficient evidence of the beneficial effect of fruit and vegetable consumption in the prevention of cancer and other chronic diseases," Sánchez states, "for this reason, one of the most effective preventative measures is promoting their consumption in the population."

Fruit for the heart

A diet rich in fruit and vegetables reduces the risk of cardiovascular disease mortality by 15%. Furthermore, more than 4% of deaths due to cardiovascular disease could be prevented by consuming more than 400 grams of fruit and vegetables a day.

Considering fruit consumption separately, no significant risk reduction was observed, whereas vegetable consumption alone was associated with a lower risk of mortality, which was even more significant for raw vegetables: high consumption reduces the risk of mortality by 16%.

With regard to cancer mortality, no statistically significant risk reduction was found, although it will be necessary to assess this according to specific types of cancer," Sánchez adds.

Nevertheless, the expert highlights that given that fruit and vegetable consumption is associated with the risk of certain cancers — colon and rectal, stomach, lung, etc. — it is to be expected that their consumption will also have a positive effect on mortality due to these tumours.

Greater effect in people with bad habits

The mortality risk reduction due to fruit and vegetable consumption was greater in those participants who consumed alcohol (around 30-40% risk reduction), who were obese (20%), and "possibly" also in those who smoked.

The authors add that this positive effect is probably due to their high antioxidant content, which mitigates the oxidative stress caused by alcohol, tobacco and obesity.

As such, these population groups in particular could benefit from the positive effects of fruit and vegetables in preventing chronic diseases and their associated mortality risk," Sánchez concludes.

By Harry Wood

Reference

1. Oyedobe O, et al. Fruit and vegetable consumption and all-cause, cancer and CVD mortality: analysis of Health Survey for England data. (open access)
http://jech.bmj.com/content/early/2014/03/03/jech-2013-203500

2. Leenders M, et al. Fruit and vegetable consumption and mortality: European prospective investigation into cancer and nutrition. Am J Epidemiol. 2013;178(4):590-602. doi: 10.1093/aje/kwt006. Epub 2013 Apr 18.

 

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