You may have heard people talk about “balancing their macros”, or wanting to “up their micronutrient intake”, or even casually throwing around the word “phytonutrients”. If that all sounds a bit too geek-speak for you, you’re going to enjoy this dive into de-mystifying the jargon around nutrition.
First up: macronutrients!
This is the big picture stuff, the three big players, carbohydrates, proteins and fats.
Carbohydrates are getting a real beat-up at the moment. You’d think they were the source of all evil the way some people talk about them “oh I can’t eat that, it’s got carbs in it!”. Carbohydrates are our body’s main source of energy – and our brains’ preferred fuel. Carbs are so important, that our body keeps a stash of them in our liver and muscles (in the form of glycogen), in case we go for a while without eating any. We get carbs from a wide range of foods, not just breads and pasta, and that’s because carbs come in a few shapes and sizes, molecularly speaking. For the purposes of this dicussion, we will divide them into sugars, starches and dietary fibre.
Sugars are tiny little molecules, and they can be out on their own – the monosaccharides, or paired up in twos – the disaccharides. Think of a monosaccharide as one little bead from a necklace, all by itself. Well, two beads together make a disaccharide. These are what used to be called “simple carbs”. You’ll find these sugars in a range of foods, both naturally occurring and added. Naturally occurring sugars are found in fruit, berries, vegetables and milk, while added sugars are found in processed foods and whatever you decide to use sugar in or on, like your morning coffee, your porridge at breakfast, or your home baking.
If you prefer some visuals, this is a cool little video I found that explains the structure of these sugars.
Next, we can join a whole lot of these beads up together, and make another type of carbohydrate – a polysaccharide (poly meaning many), and this makes the next carb on our list, starch. This type of carb used to be called complex, but that word isn’t used anymore, as we have found out more about different forms of starch, and how these different forms are digested and absorbed. Starchy carbs are found in cereals (like rice, wheat, oats, that kind of thing), potatoes, legumes (beans, lentils, chickpeas, soybeans), and bananas.
There is another way these beads can all be joined up together, but just put together slightly differently. Differently enough that we can’t digest them, as we don’t have the right enzymes (to break the little glucose "beads" apart). They stubbornly stay together through all the efforts our digestive system makes to digest them. This type of carbohydrate is the fibre in our foods. You might be thinking about now, if we can’t digest these carbs, what’s the point in eating them? This fibre makes its way through our stomach and our small intestine, and provides food for the gut bacteria in our large intestine keeping them happy, which is great for our health too.
So as you can see, it’s not a good idea to lump all carbs together and avoid them, because you will also be avoiding a lot of really nutritious foods as well as a heap of dietary fibre.
Well that’s the first of our macros taken care of, the carbs. Next we look at protein.
Protein has effectively got it’s own hype track. There’s protein-enriched this, protein shake that, protein balls, and the general impression that the more protein you eat the better. In New Zealand, with the exception of some vulnerable groups in the population, we get plently of protein. Which is good, because it’s really important for the growth, development and maintenance of the body’s tissues, as well as being a part of enzymes, hormones, your immune system, transport molecules, and loads of other important stuff. We get most of our protein from meat, chicken and other poultry, fish and other seafood, eggs, legumes, nuts, seeds and dairy products.
You may have also heard the term “complete protein” and wondered what that meant? Well, like those longer carbohydrates (the polysaccharides), you can picture proteins made up of a lot of little beads connected to each other as well. Except instead of a whole lot of glucose beads joined together, proteins are a whole lot of amino acid beads joined together. Now some of these amino acids need to come from the food we eat, and others can be made by our bodies from precursor substances. The ones that have to come from our food are called essential amino acids, and proteins that contain all of these essential amino acids are called complete proteins. All animal-derived proteins (the various forms of meat and fish, as well as eggs and dairy products) are complete proteins.
Last on the list is fat, or more accurately, lipids, which covers fats and oils.
Many years ago, fat went through what carbs are going through now – a bit of an image crisis. Like carbs, there are fats that are better for our health, and fats that can affect our health in a negative way. So like carbs, it’s not a good idea to lump all fats in together. Around the middle of the last century, research out of the United States suggested a high-fat diet was associated with an increased risk of heart disease. However, as further research was conducted, a more nuanced understanding of the role of dietary fat and disease risk evolved. Recommendations have changed as a result, and we now know that it’s the saturated fats that can have a negative impact on our health, but others, like monounsaturated and polyunsaturated fats (especially Omega 3) can actually be protective of our health. Still, it's really important not to look at these nutrients in isolation, but within a healthy lifestyle, and it's also crucial to ensure the communication of this information is clear. A recent editorial in the British Journal of Sport Medicine even suggested that rather than singling out saturated fat, chronic inflammation is more of a risk to our cardiovascular health, and its effects can be reduced by lifestyle interventions such as regular exercise and a Mediterranean-style diet. However, while a typical Mediterranean-style diet may be high in fat, it is mostly mono-unsaturated, and very limited amounts of saturated fat are consumed.
Next up are the micronutrients.
So, what are they? Micronutrients are “substances that are essential in minute amounts for the proper growth and metabolism of a living organism" (Tortora & Derrickson, 2012). They are your vitamins and minerals. Unlike the macros, you don’t get energy (in the form of calories or kilojoules) from micronutrients themselves, but they are an integral part of many of the chemical reactions involved in accessing the energy in our food.
There are fat-soluble vitamins (vitamins ADEK) and water-soluble vitamins (all the others).
As for the minerals, there are major minerals, which we require more of, and trace minerals – also called trace elements – which we need tiny amounts of. That last term gives a big clue as to what these substances are: all the minerals are elements on the periodic table! Things like iron, phosphorus, calcium, magnesium, they are all elements. Here is a link to a cool interactive periodic table if you want to take a look in more detail.
That only leaves us with phytonutrients.
Phytonutrients are compounds found only in plants, that are beneficial to our health (phyto- is from the Greek for plant). It is estimated that there could be up to 4000 different phytonutrients! Quite a few have been discovered and identified, but only a small number have been studied closely. Other words commonly used when talking about phytonutrients are phytochemicals, antioxidants, polyphenols – and a whole pile of other words that relate to various subsets of phytonutrients. Check out this site for some great ideas as to how you can boost your phytonutrient intake, and which phytonutrients do what.
Now that's a lot of info! Don't sweat it though - if you are aiming for a way of eating that covers all the macro, micro and phyto nutrient bases, it comes down to variety. The more variety in your diet, the less likely you are to miss out on any nutrients your body needs.
References:
British Nutrition Foundation. (2016). Exploring Nutrients [Website]. Retrieved February 22, 2019, from https://www.nutrition.org.uk/healthyliving/basics/exploring-nutrients.html?limitstart=0
British Nutrition Foundation. (2018). Protein. [Website]. Retrieved February 22, 2019, from https://www.nutrition.org.uk/nutritionscience/nutrients-food-and-ingredients/protein.html?limitstart=0
Dieticians Association of Australia. (2019). Legumes: What are they and how can I use them? [Website]. Retrieved February 22, 2019, from https://daa.asn.au/smart-eating-for-you/smart-eating-fast-facts/food-and-food-products/legumes-what-are-they-and-how-can-i-use-them/
Forouhi, N.G., Krauss, R.M., Taubes, G., & Willett. W. (2018). Dietary fat and cardiometabolic health: evidence, controversies, and consensus for guidance. British Medical Journal, 361. doi:10.1136/bmj.k2139
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Liu, A.G., Ford, N.A., Hu, F.B., Zelman, K.M., Mozaffarian, D., & Kris-Etherton, P.M. (2017). A healthy approach to dietary fats: Understanding the science and taking action to reduce consumer confusion. Nutrition Journal, 16(53). Retrieved from https://nutritionj.biomedcentral.com/articles/10.1186/s12937-017-0271-4
New Zealand Nutrition Foundation. (2018). Fat. [Website]. Retrieved February 22, 2019, from https://nutritionfoundation.org.nz/nutrition-facts/nutrients/fat
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Produce for Better Health Foundation. (n.d.). What are phytonutrients? [Website]. Retrieved February 23, 2019, from https://www.fruitsandveggiesmorematters.org/what-are-phytochemicals
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Tortora, G.J., & Derrickson, B. (2012). Principles of anatomy and physiology (13th ed.). Hoboken, NJ: John Wiley & Sons.
Vegetables New Zealand. (n.d.). Vegetable nutrition: Phytonutrients. [Website]. Retrieved February 23, 2019, from https://www.vegetables.co.nz/health/vegetable-nutrition/
What's Up Dude? (2016). Simple Carbohydrates. [Video Blog Post]. Retrieved February 22, 2019, from https://www.youtube.com/watch?v=q5q8NXSDV0s