This post was originally published in March of 2018, but recent advances in the literature regarding dietary fibre and our health made me re-visit this topic for an update! There has also been some debate regarding the benefits of dietary fibre from the low carb/no carb diet crowd, so I think it’s worth addressing what the science REALLY has to say about fruits and vegetables and health!
“Eat More Fruits and Vegetables”
OMG Steph we know!
If there’s one piece of nutrition advice that just about everyone can agree on, regardless of the dietary paradigm you follow (unless you’re on the carnivore diet, but that’s a whole other thing…) is that fruits and vegetables are good and we should eat more of them.
Fruits and vegetables being healthy choices isn’t news. Yet despite knowing that they’re good for us, many people I pose this question to aren’t really sure what makes fruits and veggies so good. I mean sure they have….nutrients? (yup!) and ummm, protein? (nope!) but more often than not that question is met with a shrug.
Fruits and vegetables are definitely excellent sources of vitamins and minerals in our diets.
It is recommended that we choose as many different colours of fruits and vegetables to get the biggest variety of nutrients as possible. You see, the different colours we find in produce often tells us information about what types of nutrients are in that food. The more variety we eat the more different nutrients we’ll get. Cauliflower, carrots, blueberries, bell peppers, and spinach all give us slightly different things (with some overlap certainly).
Some groups of fruits and vegetables have nutrients in common based on their color (for example the beta-carotene that makes both carrots and sweet potatoes orange is why carrots are good for our eyes). Or, the orange-red family of strawberries, oranges, and bell peppers being rich in vitamin C. Leafy greens are best-known for being a good source of vitamin K. All of these nutrients have their own ways of keeping us healthy and reducing disease risk.
So….can’t I just take a multivitamin and call it a day?
Nope, it just wouldn’t be the same!
For starters, there are many other compounds contained within fruits and vegetables that we may not have discovered or adequately researched yet. It would be very incorrect to assume that we know everything about all of the different plants we call food. Yes, scientists have isolated a number of “essential nutrients”… vitamin A, the B vitamins, vitamins C, D, E, K, and a bunch of minerals like sodium, potassium and magnesium, but that doesn’t mean we know everything there is to know about our food supply! There are a huge number of other compounds called “phytonutrients” contained within our fruits and veggies that play important roles in our health too.
What tends to happen in the supplement industry is that we know a specific vitamin or mineral (or other phytonutrient) has some potential benefits for our health, but when we isolate it, refine it, stick it in a pill and take it, the benefit no longer exists. There is more going on within our food than meets the eye. The different compounds don’t just work individually, there is a synergy going on when it comes to the way the food we eat benefits our health. There is still so much we have to learn!
Forget The “Greens” Powders
So, if we tried to get all of the benefits of fruits and vegetables in pill or powder form (like those silly “Greens” everyone adds to their smoothies), we’re not doing ourselves any favours. Not only are we paying huge sums of money for a product that probably won’t improve our health at all, but we’re fooling ourselves into believing that it’s “as good” as eating the real thing.
Fruits and vegetables also taste great! If you think you don’t like vegetables, find news ways of preparing them so you’ll actually enjoy them!
But there’s another really important reason why we need whole fruits and vegetables in our diets, and why the pills and powders just don’t cut it…
A study was published just a few days ago (January 2019) in The Lancet, in which researchers had conducted a systematic review and meta-analysis (which basically means they pooled ALL of the data from a number of studies that had previously been done), to take a look at the big overall picture of fibre and health. And we’re talking about a lot of data! 185 cohort studies and 58 clinical trials.
What they found was that dietary fibre reduces risk of death, heart disease, diabetes, and cancer, with the greatest effect seen with a consumption of 25-29 grams per day (you can check out the article yourself by clicking here!). What this means for us is that we should definitely be making an effort to increase our fibre intake.
Now, what exactly is fibre?
When we think of fibre, most of us picture bran flakes, or those little bran buds with their “woody” rough texture. Most people don’t imagine a sweet, juicy raspberry or mixed green salad, or even an avocado as being high fibre foods. But fruits and vegetables are actually significant contributors of fibre to our diets (or should be anyway if we were eating enough of them!).
It’s true, whole grains and other plant foods (lentils, beans, nuts, seeds) add A LOT of fibre to our diets too, but on a daily basis we should be eating more servings of fruits and vegetables than the other groups and with our current overly-processed diet, we’re falling short. According to Statistics Canada, only 25% of Canadian men and 38% of Canadian women are eating more than 5 servings of fruits and vegetables everyday, and that number is trending down. We should be eating upwards of 30 grams of fibre daily, but on average we’re getting about only about 10-15 grams. So, when it comes to fruit and vegetable servings, AND total dietary fibre, we’re only meeting about 1/3 of our goal.
So what does fibre do?
Fibre is considered a bit of a “freebie” when it comes to calories in our diet. We actually do not produce the right enzyme in our digestive tract to break down fibre, so we aren’t able to access the stored carbohydrate within those cells. Despite not providing us with any energy or protein, fibre does wonderful things for our bodies. It benefits our digestive tract (gut) in several different ways, and the benefits of consuming a high-fibre diet are being supported with more science all the time.
Here are a few of the ways fibre makes us healthier…
Fruits and Vegetables = Healthy Poops
Pooping regularly is actually a very good thing! Because fibre is not broken down and absorbed like the other nutrients we consume, it passes through us and winds up in the toilet. While it might seem like kind of a waste of time to bother with fibre since it just gets flushed anyway, fibre is actually doing some very important tasks as it travels along our digestive tract. Fibre adds bulk to our stool, meaning there is a larger amount of waste for us to pass, which means that we need to go more often if we’re eating more fibre.
This can help to reduce our risk of colorectal cancers. Colorectal cancer is one of the top four most common types of cancers that currently affect Canadians. Since it’s also estimated that Canadians are eating less than half of the recommended daily fibre, there is a lot we can do to help reduce our colorectal cancer risk.
How exactly does fibre reduce our cancer risk?
What’s leftover in our gut after our body has does it’s job of taking all of the valuable nutrients and energy out of our food is, well, waste. Some of those wastes aren’t very healthy for us and contain carcinogenic (cancer-causing) compounds. The longer those wastes are sitting in our gut the longer exposure they have to our healthy tissues, and the higher the chance that they can cause damage. These might be things like additives in our food (like nitrates from processed meats), or naturally occurring wastes that are part of normal digestion. Obviously another great way to reduce our colon cancer risk is to avoid processed meats and nitrates they contain, but increasing our fibre intake is a key action we can take as well!
Fruits and Vegetables and The Microbiome
Another really interesting way fibre benefits us is by feeding our gut microbiome. Don’t get freaked out, but there are actually trillions of bacteria living in our digestive tract at this very moment. There is so much bacteria living inside of us (and on our skin actually), that if you were to add up the total human DNA vs bacteria DNA both on our bodies and within, we’re actually more bacteria than human! (Now THERE’S your fun fact for the day!).
Each of us has a unique gut microbiome that starts developing from the time we’re born. Babies have a sterile digestive tract while in the womb, but that quickly changes as they are born and are exposed to the outside world. Infants born via c-section have a different microbiome compared with babies who are born vaginally (cesarean sectioned ones have a microbiome more similar to their mother’s skin, vs ones born through the birth canal).
Same goes for breastfed vs formula fed infants, their microbiome differs based on the varieties of bacteria they are exposed to. As we age our microbiome is being constantly fed information about the outside world via the food we eat, allowing our bodies to adapt to our changing environment.
These bacteria need to eat just like us. On this planet there are bacteria that have adapted to thrive in just about every situation. With oxygen, without oxygen, some that eat protein, some that eat fat, some that eat gasses, some that even eat the plant fibres that pass through our digestive tract. Certain bacteria ferment the fibres, which create gasses that help to feed others. There’s an amazing little community in there that all work together and compete with each other to maintain balance in our gut.
If you can imagine a person consuming a low-fibre diet, the balance in our gut can really suffer if the right types of bacteria aren’t getting the fuel they need the thrive.
These helpful little bacteria provide us with a number of health benefits, like improved immunity (it is estimated that 90% of our immune system is located in our gut), better absorption of nutrients, and affects how our bodies respond to and use food in ways we never used to consider. New research that is emerging is even showing a link between the health of our microbiome and our brain. There may be an important link between a healthy gut and mental health, which is just one more reason to take care of your microbiome!
A Note About Probiotics and Prebiotics
You’ve most definitely heard of probiotics (like in yogurt, or in supplement form). These are the actual bacteria that are known to benefit us that we can purposefully consume to increase the “good” types of bacteria in our gut. Fermented foods like yogurt or kombucha are great sources of probiotic bacteria. Some people with digestive issues can greatly benefit from taking a probiotic supplement if it is suspected that their natural microbiome may be suboptimal (for example after taking a round of antibiotics)
Prebiotics on the other hand are not the bacteria themselves, but food for those bacteria. Namely specific types of fibres that our gut bacteria are known to use for fuel. It is important to note though that ALL fibre is beneficial in it’s own way and we should be focusing on getting a variety of fibres from fruits, vegetables, whole grains, nuts, seeds, and pulses to maintain good gut health. Eating a varied diet with whole foods should always come before taking a supplement.
What about pesticides/chemical residues on fruits and vegetables?
I hear this question all the time! Many of us are concerned about the harmful side effects of chemicals in our food, and organic might seem like the way to go to make sure our foods are completely chemical-free….right?
Unfortunately, that’s not exactly the definition of “organic”. There really is no globally accepted definition of the word. It sounds like it should be synonymous with “chemical free” but in reality it simply means that the food cannot be grown with the use of synthetic (man-made) chemicals. Naturally sourced chemicals are still ok to use on organic produce. What’s really important to remember here is that natural does not always mean safer, AND sometimes are not as effective as the synthetic ones, meaning more needs to be used to get the job done. When using synthetic pesticides farmers can use far less because they are more effective.
The added cost of buying organic produce also is a real barrier for many people out there. For lower income families caught between the fear of conventionally grown produce and the inability to afford organic they end up buying less produce overall, which is definitely not a positive outcome. If you’re really concerned about where your food comes from and how it is grown, my advice would be to grow it yourself! Planting a garden is a wonderful way to get better access to fresh seasonal produce for VERY little cost. When it comes to fruits and vegetables just getting enough is the most important thing.
I’d still recommend washing produce before consuming it. Not because I’m worried about pesticides in my food, but imagine being at the grocery store and seeing everyone picking through the piles of apples, touching every one as they go. Do you think all of those people have clean hands? I’m definitely no germaphobe, but giving your fruits and vegetables a quick wash before eating them isn’t a terrible idea, especially if you’re going to eat the peel. Which you always should, because that’s where most of the nutrients and fibre are contained!
The Bottom Line
So, despite advances in nutrition science and our ability to create fancy new supplements full of promises of optimizing health, getting back to the basics is still the best way to keep us AND all our resident bacteria healthy. There is just no replacement in our diet for all of the important and wonderful things that fruits and vegetables do for our bodies, and if we treat our microbiome well, it will treat us well in return!
It might be boring, broken-record advice, but getting your 7-10 servings of fruits and vegetables every day is still one of the most tried and true ways to stay healthy. Your whole body will thank you!
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