How to get the most out of your vegan dietDec 12, 2019
What’s the healthiest diet? The one with no limits.
“Food” conjures a different image for each of us, and that’s because there are so many possible combinations of plants, flesh, oils, fruits, spices and preparation methods. Each of these has a unique nutrient matrix – vitamins, minerals, polyphenols, antioxidants all wrapped up in fibre, carbohydrate, fat and protein in specific ratios.
It's a complex thing, biology.
We introduce these biochemicals into our bodies and they interact with our metabolism. The complexity of all these chemical interactions is mind-boggling and is still being unravelled, but we do know of many vital vitamins, minerals and the rest that have beneficial effects.
There are recommended daily intakes set for zinc, magnesium and B-vitamins. There are well-established effects of adequate protein intake on recovery from exercise. Fibre promotes a healthy gut microbiome and saves on toilet paper.
Better yet, these unique nutrient combinations found in whole foods have a synergistic effect. It’s not the same to take a large dose of synthetic B-vitamins from a pill instead of the naturally occurring levels found in a steak (along with the accompanying minerals, fats and proteins). That’s not to say synthetic vitamins are inferior. They’re just delivered in a different form, dose and nutrient matrix than ones found in whole foods.
Any restrictive diet makes it harder to be healthy. A diet that allows every available option makes getting a wide range of nutrients from tasty food much easier than one that cuts out food groups. The more restricted the list, the fewer options we have to reap sustenance and pleasure from food.
But cutting out foods is sometimes warranted. I try not to keep ice-cream in the house because I have very little self-control when it comes to my sweet tooth. I don’t have to remove it entirely, but it’s reasonable to do sometimes.
You might find another reason to cut out a chunk of the standard food pyramid. Perhaps your conscience won’t allow you to aid and abet factory farming, or maybe you want to minimize your impact on the environment. Maybe you just don’t like the taste of meat.
Vegetarianism is a reasonable route to take in these cases, but there’s a problem – to get the most out of training, to support your health, you need to be more conscientious if you’re going to cut out entire food groups. “Flexitarians” are happy with occasionally consuming meat, eggs and dairy, whereas pescatarians include only fish. Lacto-ovo vegetarians include dairy and eggs only, but vegans will only eat plants. Fruitarians go a step further by limiting themselves to fruit, nuts, seeds and some select vegetables.
Omnivores place no restriction on eating the flesh or milk of animals. While I stand by the rule of thumb that more food options increase the probability of eating a healthy diet, omnivores aren’t automatically healthier than vegans. I’m an omnivore and an unfussy eater, but I still don’t get enough fibre or omega 3 fatty acids sometimes, so I resort to necking mouthfuls of psyllium husk and taking fish oil to shore up these shortcomings. Likewise, a vegan diet doesn’t guarantee health. I’ve had my fair share of vegan clients who somehow exist mostly on toast and beans.
Focusing more on plant foods does make it easier to get enough micronutrition from all the fruit and veg. The downside is that there are some nutrients that are hard to come by in plant foods.
Here’s a reference table, with explanations that follow (I’ve avoided listing how much to take of these nutrients since it’s important for you to base most of these on blood tests from your doctor):
Rogerson D. Vegan diets: practical advice for athletes and exercisers. J Int Soc Sports Nutr. 2017;14:36. Published 2017 Sep 13. doi:10.1186/s12970-017-0192-9
Amino acids are bricks that are built up in various combinations to make peptides and then proteins in the body. Protein structures exist everywhere and play a variety of roles, from cellular transport to manufacturing to scaffolding to machinery. Think of a factory with all the tools, machinery, storage areas – proteins make up all of these in a cell.
Different structures need different combinations of amino acids, and these are supplied through the diet. The proteins we eat are broken down into amino acids and these are directly used to assemble proteins in the body.
Each food has its own ratios of amino acids contained within, and while animal sources of protein contain a rich array of amino acids, most plant foods are deficient in one or more. Common examples of the limiting amino acids in plant-based proteins include lysine, methionine, isoleucine, threonine and tryptophan.
We also tend to have a harder time digesting plants and extracting the amino acids within. Scientists have attempted to create scales that compare the digestibility scores of protein sources. Each scale has its drawbacks, but in general plant proteins score as less digestible than animal counterparts.
The solution is to eat a variety of plant proteins to cover your bases. Another option is to simply eat more protein, above what you would eat if including animal sources. In particular, leucine is an amino acid that signals muscle growth and most plant proteins aren’t rich in leucine. Some rich sources of leucine are soybeans and lentils.
Including a protein supplement is a convenient way to bump up protein intake. There is a wide range of products available that derive their protein from various sources like soy, pea, rice, hemp, or a blend of these.
VegFAQs has a cool amino acid profile tool that could be useful for nerdier readers.
There are also many different types of fats that can be obtained via the diet.
Fats are classified by their chemical structure. Each fatty acid has a carbon chain, or skeleton that other atoms can join on to. Saturated fats have all of their carbon atoms occupied (or "saturated") by hydrogen atoms. Unsaturated fats have only some hydrogens parked on top of carbons.
The omega number (as in omega-3 or omega-6) tells us where the first double bond between carbon atoms occurs.
Enger, Eldon D. and Ross, Frederick C., Concepts in Biology, 10th Ed., McGraw-Hill, 2003.
These aren't necessary for the layman to know. All you need to understand is that different fat types have different biochemical effects on the body because of their differing chemical structures. The scientific consensus is that we need a balance of fat types for optimal health.
Unsaturated fats are most commonly found in plant foods and these are usually under-consumed by omnivores, so that’s good news for vegans. However, much of the unsaturated fat from plants is of the omega-6 variety. It’s important to eat a balance of omega-3s and omega-6s, so plant-based dieters often need to find a good source of omega 3s.
Since vegan diets exclude fish, it’s typical to see lower long-chain omega-3 intake (EPA and DHA are the two fatty acids we’re after).
These are involved in cardiovascular health, the immune system, exercise adaptations and cognitive health since they affect inflammation (a form of signalling in the body). Vegan sources of omega-3’s aren’t easily converted into the long-chain form that we want (the shorter chain omega-3 is ALA, rich in flax seeds, walnuts, and chia seeds).
The best option to get the same type of fats found in fish is to supplement with algae-derived omega-3s.
Vegans are at a greater risk of developing a deficiency in vitamin B12 (cobalamin), which could result in neurological damage. While B12 is abundant in animal foods, it’s rare to see it in plants. Some cereal products are fortified with B12, and nutritional yeast is another good source. It has the bonus of tasting cheesy and can really spice up a vegetable dish.
Since digestion and absorption of B12 is not stellar, a supplement might be helpful as insurance against deficiency.
It’s common for vegans and vegetarians to eat a similar amount of iron to their omnivorous counterparts. Whole grains and legumes are rich sources of iron, but there is a question of the bioavailability of plant-sourced iron.
Female vegans in particular tend to have a lower iron status for obvious reasons. Iron-deficiency anaemia is caused by insufficient consumption of iron (or insufficient absorption of iron). Anaemia is a decrease in red blood cells or haemoglobin, leading to symptoms such as tiredness and reduced exercise tolerance.
Even without the extreme form that leads to anaemia, iron deficiency can reduce endurance capacity and impair the positive adaptations that occur with endurance training.
Iron comes in two forms: haem and non-haem. Haem (as in haematological – relating to blood) is far more bioavailable and is carried in the blood of animals, whereas the non-haem form exists in plants.
Whole grains and legumes also contain anti-nutrients. These are dietary inhibitors like tannin (found in coffee, chocolate, tea) and phytates that reduce the absorption of non-haem iron. They sound scarier than they are, and it simply means you might need to make an effort to eat more iron-containing foods if you only eat plants.
These inhibitors can be reduced by soaking, sprouting or fermenting grains and legumes. Consuming a source of vitamin C along with non-haem iron can enhance its absorption, so that’s another point for whole foods over supplements.
Achieving iron sufficiency can be done with plant sources only, but it’s worth getting regular blood tests to make sure your levels are adequate. If you’re someone who is at risk of iron deficiency (for example, a female who experiences heavy menstruation) then supplementation might be necessary and can be recommended by your doctor.
Zinc plays a wide variety of roles in the body, including aiding cell growth and repair. Like iron, zinc is abundant in plants, but its absorption must be considered. Common vegan sources of zinc include beans, whole grains, nuts and seeds (like hemp and pumpkin seeds) – the same foods that contain the anti-nutrients that hinder iron absorption. Processing by soaking, sprouting or fermenting will reduce phytate content.
There’s an argument that poor mineral absorption from plant foods is overstated, since the body can regulate losses and uptake of micronutrients from the intestines to some degree. When the body detects a low tissue concentration of zinc, for example, intestinal transporters become more active in hoovering up any available zinc, iron or calcium in the gut. However, it’s still worth paying attention to by being conscientious of eating foods rich in these nutrients.
Most people associate dairy with calcium, and this is probably the richest source of calcium in most peoples’ diets. One study showed that Canadian vegans eat almost half the amount of calcium that omnivores or ovo-lacto vegetarians do. It’s important for bones health and many other aspects of metabolism that adequate calcium is consumed, and good sources in the vegan diet are beans, pulses and green vegetables (such as bok choy, spinach, kale, broccoli). There are also plenty of fortified foods available, like calcium-enriched milk alternatives or calcium-set tofu.
Important for thyroid hormones, which help control metabolism. Like any other micronutrient, iodine has a healthy range and maintaining levels above or below this range can lead to thyroid dysfunction. Depending on their favourite foods, vegans and vegetarians could eat far too much or far too little iodine.
Iodine content in foods vary according to the soil-iodine content (when growing produce), the farming methods used during production, the season it is grown in, and the species of fish (if non vegan). The richest sources of iodine are sea vegetables like seaweed, but concentrations vary dramatically. Iodized salt is also easily found in grocery stores and can be used as a source of iodine where insufficient intake is a problem.
Goitrogens, found in cruciferous vegetables such as cabbage and cauliflower, decrease iodine use in the body. Eating these in excess could have consequences on thyroid function.
This is important for a wide range of physiological functions, and it’s primarily synthesized after sun exposure to the skin. There are also some dietary sources, however, like liver and fortified foods.
The main concern for vegans is with supplementation. Cholecalciferol (D3) is the most common supplemental source of vitamin D, and it’s usually an animal-derived version. Recently, lichen-derived D3 has become available.
Ergocalciferol (D2) is a vegan-friendly alternative but it’s less bioavailable than cholecalciferol.
You can read more about creatine here. Since it’s mostly stored in muscle, plant-based diets are low in creatine. I consider creatine supplementation a vital component of a healthy plant-based diet, especially if you have specific strength goals.
That's everything I can think of. I'm sure you can now better understand my assertion that more variety in the diet allows us to think less about which micronutrients might be missing. Eating a plant-based diet neither guarantees nor debilitates health. It's all in how you do it, and that goes for any diet.
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