The Science of Nutritional Needs

Food and drink, health care, diet and nutrition concept. Assortment of organic vegan non diary milk from nuts in glasses on a kitchen table. Top view flat lay background

If you do decide to try Veganuary, or indeed adopt a vegan lifestyle fully, then you need to be clued up on your body’s needs to avoid ill health. Here are the whys and the wherefores:


A macronutrient (just like carbohydrates and fats), proteins contain essential amino acids. The body needs these for the building and repair of tissue, bone, muscle, cartilage, skin, and blood. In addition, amino acids produce hormones and enzymes and contribute to further bodily chemical processes.
There are 9 essential amino acids and unfortunately on the whole plant foods are particularly low in lysine. Luckily, legumes (including soya) are a very good source of lysine; so too the grains quinoa and amaranth.


From what a person consumes, only about 25% to 30% is normally physically absorbed. Calcium-set tofu and fortified plant milks have the same absorption rate (30%) as cow’s milk, while other plant foods can offer between 5% and 65% absorption rates.
Caution needs to be taken around the established wisdom of green leafy vegetables being replete in calcium as many also contain oxalates, which bind and reduce calcium absorption. Such high-oxalate foods include the revered spinach. Instead, turn to kale and broccoli, as their low-oxalate content means our bodies absorb the calcium very well.
Additionally, soaking beans and nuts – the calcium content of which is normally difficult to benefit from – increases absorption capabilities.


Dietary fats are essential for health; in particular, fatty acid Omega-3s are crucial for optimum brain performance. These can be found in plant-based sources such as hemp seeds, flaxseed, chia, walnuts, leafy greens, pumpkin seeds, soya products, and rapeseed oil. These sources contain the shorter chain ALA (alpha-linolenic acid), converted by the body into the longer chain fatty acids DHA (docosahexaenoic acid) and EPA (eicosapentaenoic acid), both of which promote overall health.
A fuel as well, fats aid the absorption of other vitamins and minerals. Monounsaturated fats can be found in olives, macadamia nuts, avocados, and peanuts.


Iron plays an important part in the health of red blood cells, forming the haemoglobin which transports oxygen through our blood.
Although plant foods contain plenty of iron, this doesn’t lend itself to being absorbed as easily as that derived from animal products, due to the presence in plant-foods of phytic acid (or phytate). To aid iron’s absorption, consume vitamin C-dense foods or beverages at the same time, as vitamin C offsets the binding effects of phytic acid. Avoid coffee and tea while eating.
The increase in iron absorption by the addition of a glass of orange juice or half a cup of cauliflower with a plant-based meal has been shown to be as much as four or six times greater. Additionally, the inclusion of fermented foods intensifies this process even further (think a slice of sourdough bread to accompany).


Crucial for the production of DNA and maintenance of nerve cells and the general cellular division, vitamin B12 also keeps homocysteine levels at a healthy level (increased levels raise the risk of cardiovascular disease and cognitive decline).
Although omnivores will claim that if you have to supplement something it’s not a balanced diet, the vitamin B12 found in animal products comes in fact from the creatures’ own diet and intestinal bacteria.
There are two reliable sources of vitamin B12 in the vegan diet: supplements and foods fortified with it (for example, nutritional yeast grown on a B12-rich medium). Aim for 2 servings of between 2 to 3 mcg per day, ideally consuming them separately as snacks to other meals for optimum absorption.


An important mineral, necessary for thyroid function and overall metabolism, sea vegetables are the best vegan source of iodine (with milk and seafood, conversely, being the omnivorous sources). With low levels having been associated with an increased risk of cancers like breast and ovarian, a sprinkle of seaweed on a bowl of jasmine rice is an enjoyable side to a main vegan meal.

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