Fruit and Your Health: Yay or Nay to an Apple a Day?
Does an apple a day keep the doctor away? Once commonly accepted as a health boon, fruit is now seen by many people as something to limit, due to its high sugar content.
It’s true that fruits contain a lot of sugar. A medium apple, for example, contains about 20 grams of sugar, of which about half is fructose, the much maligned simple sugar. It’s also true that, in terms of macronutrients, fruits are basically pure carbs — they typically contain very little fat or protein (with notable exceptions, like avocados).
However, it is NOT true that we should be avoiding fruits for fear of negative health impacts.
What does the science say?
Eating more fruit is consistently linked with a lower risk of obesity, diabetes, cardiovascular disease, and some cancers (see studies in appendix). This is the opposite of what you would expect if fruits were harmful.
While many of the studies behind these links are come from epidemiological studies, which can’t prove causation, and must be interpreted with caution, the scientific body of evidence has several confidence-inspiring features:
(1) It’s consistent across many large studies;
(2) It shows a dose response;
(3) It has a strong mechanistic basis.
Undoubtedly, some of the apparent health benefits of fruits come from a healthy user bias (those who eat more fruit are probably engaging in a healthier lifestyle overall). Yet, the general trend towards “more is better” and the strength of evidence make it highly unlikely that this is the whole story.
Why Is Fruit Linked To Better Health Outcomes?
The link between fruit and health is though to be a combination of these four factors.
1) They provide high satiety per calorie, thanks to their water and fiber content. In other words, fruits make us feel full on few calories. Indeed, studies show that eating more fruit can lead to an overall decrease in calorie intake.
2) Their high fiber content supports gut health. You can’t digest fiber, but the “good” bugs in your gut gobble it up, work metabolic magic, and spit out health-promoting substances like short chain fatty acids.
3) They are loaded with health-promoting vitamins, minerals and phytochemicals. Antioxidants, in particular, are thought to play a role in disease protection.
4) They crowd out less healthy foods. Fruits rank very highly compared to other foods in terms of nutritional upside versus downside, so there chances are good that they are displacing less healthy options. This benefit is indirect but real!
Too Much Of A Good Thing?
It’s impossible to set a single number for the “right” amount of fruit, because it depends on many factors, including the rest of your diet (which nutrient needs are met and which are not), your metabolic health, and your gut health. Most studies show the biggest benefits moving from no fruit to around two fruits per day. Some other studies show even more benefits of going beyond this. I like the simplicity of the Canada Food Guide, which suggests aiming to fill half your plate with fruits and veggies.
At the same time, going bananas on fruits can raise the risk of nutrient deficiencies, particularly when fruits crowd out all others food groups. Despite their rich and diverse content of vitamins and minerals, an all-fruit diet is likely to be short on protein and fat, as well as certain minerals (such as iron and calcium).
Still Not Convinced?
I’m in good company with my conclusion to embrace whole fruits. Multiple national and international reports on sugar and health have concluded the same thing: we should be limiting our intake of “added sugars” or “free sugars” but NOT those found in fruits and veggies (and veggies, including the sweet ones). For example, the World Health Organization, Health Canada and the US National Dietary Guidelines.
If you’re still not convinced — it’s your loss!
NB: Those with health conditions related to blood sugar management should consult with their physicians regarding appropriate fruit consumption.
The Bottom Line
An apple a day really can help keep the doctor away! Or, better yet (but not as catchy):
“An apple, an orange, and a banana a day keeps your sweet tooth at bay and makes your gut say “hooray”.
At the same time, don’t go overboard. To safely cover your nutritional bases, include a variety of foods spanning legumes, nuts, veggies, and whole grains.
NB: The health story for juice is not the same as the story for whole fruits… stay tuned.
Photo credit: https://www.instagram.com/sncxkitchen/
These are just a few of the recent scientific reviews looking at links between fruit consumption and health outcomes. This article is not intended to be a comprehensive review of all of the literature.
- Impact of Whole, Fresh Fruit Consumption on Energy Intake and Adiposity: A Systematic Review. (Guyanet, 2019)
- Fruit consumption and adiposity status in adults: A systematic review of current evidence. (Hebden, 2017)
Cardiovascular disease and cancer
- Fruit and vegetable intake and the risk of cardiovascular disease, total cancer and all-cause mortality: A systematic review and dose-response meta-analysis of prospective studies (Aune et al, 2017)
Type 2 Diabetes
- Food groups and risk of type 2 diabetes mellitus: a systematic review and meta-analysis of prospective studies. (Schwingshackl L, 2017)
I am formally trained in human genetics (PhD) and spent the first decade of my career working in cancer research, drug development, and personalized medicine.
My new career chapter is dedicated to empowering others to make informed food choices, rooted in facts not fears. I’m particularly passionate about helping people to fall in love with the plants on their plates.
See more of my work (and healthy recipes) at https://FueledbyScience.com
Originally published at https://fueledbyscience.com on November 22, 2019.