THE WASHINGTON POST – A new study backs up the long-standing nutritional guideline that consuming five daily servings of a variety of fruits and vegetables, from apples to zucchini, can help you live longer. But if you consider fruit juice or french fries among those servings, you may have to rethink your diet.
“People who eat five servings of vegetables and fruit daily have 13 per cent lower risk of all-cause death compared to people who eat two servings of fruit and vegetables per day,” said Dong Wang, a faculty member at Harvard Medical School and Brigham and Women’s Hospital in Boston, and one of the study’s researchers.
The study found that people who consumed five daily servings – specifically two fruits and three vegetables – had a 12-per-cent lower risk of death from cardiovascular disease, a 10-per-cent lower risk from cancer and a 35-per-cent lower risk from respiratory disease, compared with people who ate just two daily servings. One “serving” is a half-cup of any vegetables or fruits, or a whole cup of salad greens. You get the same beneficial vitamins, minerals and fiber in both, but vegetables are slightly lower in calories and sugar, which is why the guidelines generally recommend slightly higher consumption levels for vegetables.
Based on these results, Wang encourages all to double-check their habitual intake, and make improvements if needed. On average, most Americans eat only one serving of fruit and one-and-a-half servings of vegetables daily, far less than what’s recommended.
“It is very important to increase fruit and vegetable intake to at least five servings per day in order to enjoy a healthier and longer life,” Wang said.
The findings, published in the journal Circulation, included two prospective cohort studies (which are long-term studies focussing on a specific group of people) of more than 100,000 American men and women who were followed for up to 30 years. Those two cohort studies were then added to 24 other cohort studies from across the globe to conduct one large meta-analysis (a collection of many smaller studies, which are grouped together to determine overall trends) on more than 1.8 million participants.
Collectively, the studies showed a strong correlation between the consumption of fruits and vegetables and the reduced risk of all-cause mortality, but the studies do not show cause and effect.
Interestingly, Wang’s research showed that having more than five servings of fruits and vegetables daily was not associated with a more favourable outcome – the risk reduction plateaued at five daily servings.
Of course, there’s no harm in getting more than five daily servings. Wang’s study looked specifically at mortality, but there are other reasons to consume vegetables and fruit, including disease prevention.
Karen Collins, a registered dietitian nutritionist and the nutrition adviser to the American Institute for Cancer Research, said that consuming more than five servings daily is linked with a further decreased risk of developing cancer. And the Dietary Guidelines for Americans recommend 2.5 cups of vegetables and two cups of fruit daily for overall health, which amounts to about nine servings per day.
Since Americans are nowhere near consuming nine servings, it’s comforting to know that Wang’s study found that even five servings a day will have beneficial effects on all-cause mortality. As a public health measure, aiming for five servings per day seems more achievable.
“It’s critical that we meet people where they are, and emphasise that each step forward from diets with minimal vegetables and fruits makes a difference,” Collins said.
Variety is key, since fruits and vegetables all contain different beneficial nutrients and antioxidants. Wang’s study showed that almost all fruits and vegetables, including leafy greens, citrus fruits and berries, were associated with lower mortality, but there were some exceptions.
Fruit juices and starchy vegetables such as peas, corn and potatoes were not associated with reduced risk of death or chronic diseases. It may be due to their higher glycemic load compared to other fruits and vegetables, which means they have a greater ability to raise blood sugar levels.
To be clear, the study results didn’t find harm or an increased risk of mortality from these options. But they didn’t show the same links to reducing total mortality either. Consider them neutral.
The study’s findings do not support the recommendations in the recently updated Dietary Guidelines for Americans, which treat all fruits and vegetables equally. The Guidelines count fruit juice as a serving of fruit, and recommend up to five cups of starchy vegetables per week.
Potatoes “account for more than a quarter of US vegetable consumption”, Collins said. The problem? At least half of the potatoes that Americans eat are in the form of french fries or potato chips, which are high in salt and fat. There’s no need to avoid potatoes, but choose options that are roasted or boiled most often, rather than those that are deep-fried.
I’m frequently asked if canned and frozen options are nutritious, and whether it’s better to buy organic verses conventional produce.
The good news? Your five daily servings can be met from a variety of fresh, frozen or canned fruits and vegetables, whether conventional or organic. Whichever fruits and vegetables are available, affordable and appealing are good choices for you.
Studies show that freezing and canning preserves nutrients, which often makes these options even more nutrient-dense than their fresh counterparts. For example, one study found that frozen kale had more antioxidants than fresh kale. Another study showed that vitamin C levels in canned peaches are four times higher than in fresh peaches. They are all good choices.
“Eating produce is what matters, and all forms fit,” New York City-based chef and registered dietitian Abbie Gellman said. She explains that canned and frozen produce is picked at its peak and packaged within hours of harvest, which means it retains flavor and nutrient content.
“Canned and frozen fruits and vegetables are a great way to ensure that you always have produce available year-round,” Gellman said. Plus, they are good options for people whose barriers to consuming five servings per day include the high cost, low access, poor quality and lack of variety of fresh fruits and vegetables. Canned and frozen options can help reduce food waste, save money and offer convenience. And what about organic options? They are fine if you can access and afford them, but it’s not necessary to purchase organically grown produce.
“We know from research and experience that when you limit options, you limit opportunities to consume more,” said dietitian Wendy Reinhardt Kapsak, president and CEO of Produce for Better Health Foundation, a national non-profit organisation promoting fruits and vegetables. “Both conventional and organic fruits and vegetables are healthy and equally nutritious choices.”
Finally, sometimes people ask if the sugar content of fruit is cause for concern. It isn’t if you aim for two servings per day. The reality is that Americans get about 57 per cent of calories from ultra-processed foods including sweets, but fall short on fruit consumption – so the sugar in fruit is not a public health issue when eaten at recommended levels.
Wang added that it’s vital to consider the nutritional properties of the whole food, rather than one nutrient. Beyond sugar, Wang explained that fruits contain fiber, vitamins A and C, potassium, polyphenols and folate, which are important nutrients for overall health.