If you decide to adopt a vegan or vegetarian diet or you are cutting down on the amount of animal products you consume, then it is extra important to learn how to optimise the nutrients you eat from your plant-based diet. This is because there are not that many like-for-like swaps from animal to plant foods in terms of both macro (protein, fat and carbs) and micronutrients (vitamins, minerals, essential fatty acids, phospholipids) and some of the naturally occurring chemicals in plant-based foods can actually block the absorption of some key nutrients.
It’s pretty normal when going plant-based to head to the supermarket and buy easy vegan swaps such as veggie textured protein and vegan milk, cheese and yoghurt. However, remember that most shop-bought plant-based cheeses and yoghurts do not contain any calcium at all and usually little to no protein; and many of the veggie textured protein sources do not contain much bioavailable (easy to absorb) iron.
Even when plant-based foods are fortified such as vegan “milks”, the manufacturers rarely use the more bioavailable forms of these nutrients, which means that they are harder to digest and assimilate. Calcium carbonate is a form of calcium that people on reflux medications find difficult to absorb. Vitamin D2 and cyanocobalamin B12 are man-made synthetic forms of these vitamins which are a lot harder for the body to uptake. So even if these are added to your foods, you may need to top up on these core nutrients from other food sources, as well as take food supplements to ensure you get enough of the nutrients to feel well.
You need to learn how to prepare, cook and serve plant-based foods properly, so you get the most out of the food you are eating. You may also need to eat a greater volume of food to get enough nutrients to keep you happy, healthy and well. Here are my top tips on how to get the most out of eating a plant-based diet and avoid any nutrition pitfalls along the way:
Heme & Non-Heme
Iron is an essential mineral which transports oxygen around the body and is important for both energy levels and mood. Low ferritin levels have been associated with breathlessness, fatigue and anxiety. Ideally, ferritin should be over 50 to feel well, and at the very least it should be over 27 for a menstruating woman. Iron from food sources comes in two forms: heme and non-heme.
Heme iron is only found in animal flesh like meat, poultry, and seafood and non-heme iron is found in plant foods like whole grains, nuts, seeds, apricots, lentils, kidney and black beans and leafy greens. Meat and poultry also contain about 55-60% non-heme iron, as animals consume plant foods. It’s the non-heme plant iron that is added to some fortified foods like breakfast cereals.
Non-heme iron is harder to absorb than heme iron, and so you need to ensure you are eating plenty of foods containing these and do your best to optimise absorption. The poor uptake and potential to block in non-heme iron uptake is partly why it is advised for a vegetarian or vegan to consume up to 1.8 times more iron than a meat eater to keep their iron levels at a healthy level. You won’t need quite as much if you optimise your iron uptake by following these guidelines:
What Helps Iron Absorption?
Plenty of Vitamin C – consume iron rich plant-based foods alongside Vitamin C-rich foods. This could be lemon or lime juice squeezed over food or added to a dressing, it could be some fresh parsley sprinkled on top of food or some crunchy raw bell pepper batons. It could be by eating an orange or other citrus fruit for pudding.
What Hinders Iron Absorption?
Phytates – which are in wholegrains, nuts, seeds, pulses and soya and can block the uptake of iron. Grinding, soaking, sprouting, and fermentation methods can be used to remove or degrade phytate to a varying extent. Soak rice, quinoa, pulses and other grains for a few hours before cooking and buy activated nuts and seeds. Aim to eat fermented foods like apple cider vinegar, miso, tempeh, kefir, sourdough bread. Avoid soya milk, cheese and yoghurts which are high in phytates.
Avoid Calcium – calcium taken at high levels can potentially block the absorption of iron. A medium sized glass of cow’s or fortified plant milk (165mg calcium) is thought to be enough to hinder the uptake of iron. Therefore drink milk away from an iron-rich meal and do not take calcium supplements at mealtimes.
Avoid Tea & Coffee – in a similar vein to calcium, the tannin in tea, coffee and some herbal teas can hinder the absorption of iron. Avoid drinking coffee and tea at mealtimes and drink these away from food. This is the same for green tea.
Avoid Antioxidant-Rich Food Supplements – Turmeric, Milk Thistle, Resveratrol and Quercetin are popular food supplements. These have the potential to remove iron from the blood and reduce iron stores. It is best to avoid these when you are trying to build up iron stores. Simply take separately from iron-rich foods and avoid in large quantities if you are at risk of being anaemic.
We need to consume calcium in conjunction with other minerals such as magnesium and boron to build and maintain strong bones.
What Hinders Calcium Absorption?
Calcium carbonate/Calcium phosphate – Calcium carbonate is added to many plant-based milks and is the main ingredient in most calcium supplements. Calcium carbonate is the ionic salt that makes up chalk. Calcium carbonate is absorbed at the same rate as cow’s milk and that is why the manufacturers choose this form. However, the carbonate form needs stomach acid and other gastric juices to be absorbed. Calcium carbonate absorption will be compromised if you have low stomach acid or you are taking acid suppressing medication such as PPI’s for reflux including omeprazole or lansoprazole. Calcium phosphate is also added to many plant-based “milks” including Oatly and it is harder to absorb than carbonate.
Ideally choose foods fortified with or supplements made from calcium citrate or algae-based calcium, especially if you are taking proton pump inhibitors (PPI’s) or your digestion or gut health is compromised.
Reduce Phytates – Calcium and magnesium levels seem to be lower in people who consume high phytate diets, so soaking almonds and sprouting oats is a good idea. Soya has the highest phytate content which reduces calcium absorption, so even though it contains calcium this is not an ideal food to eat if need to optimise your calcium levels. One way to help offset the effects of phytates is through probiotic strains such as lactobacillus which are in milk kefir, water kefir and some coconut kefir or through lactobacillus supplements.
Vitamin D – Getting lots of sunshine or topping up with a Vitamin D supplement will also help the absorption of calcium.
Iodine is critical for a healthy metabolism. It’s an important nutrient for thyroid health and without enough iodine over time, a person can develop hypothyroidism. This can manifest in symptoms like fatigue, weight gain, poor memory, thinning hair, being cold all the time and constipation. On the other hand, consuming too much iodine can also make you very ill over time.
If you are not eating fish or dairy products, then nori seaweed sheets or a seaweed condiment sprinkled into beans stews and tomato sauces a few times a week is a good idea. Seaweed varies very widely in the amount of iodine it contains: 1 gram can range from 16 to 2,984mcg!
Quite a few of the new vegan milks have are fortified with iodine in the form of iodised salt so if you are drinking lots of these then scale back on the extra seaweed consumption. Pink Himalayan salt contains a little iodine, sea salt contains a trace. Seagreens make a seaweed-based range of supplements, salt and food condiment.
Zinc is essential for a strong immune system, for growth, for a healthy digestion and for developing a sense of taste and smell. It is also a critical nutrient for learning, memory, reasoning, and eye-hand coordination. Puberty is a time when children need a huge amount of zinc and they can become depleted very easily. A zinc deficiency is also often implicated in those with eating disorders and may be the precursor to a change in relationship with food.
It’s easier for a vegetarian to consume zinc than a vegan as it is plentiful in dairy and eggs. Whereas vegans need to rely on wholegrains, nuts and seeds and there is also a little zinc in maple syrup, potatoes, green beans and kale. Supplementation for those low in zinc should be around 15mg daily.
What Hinders Zinc Absorption?
Again the phytates in grains, seeds and beans/legumes can block the absorption of zinc from that food. Grinding up nuts and seeds, eating them as nut butters and nut seeds can help. Also soaking, germinating, and fermenting can be used to reduce phytate levels. There is more phytate on the outside of wholegrains like brown rice and it tends to be evenly distributed through the whole of the legumes and seeds. Soak your grains, nuts and seeds and enjoy sprouted seeds as sprinkles on salads.
Vitamin B12 is essential for our energy, immunity and central nervous system function, and without enough we can get tired, pale and breathless. A B12 deficiency can also affect digestion and appetite. Low B12 may also affect learning and memory and is important for neurological function. A B12 deficiency can also cause almost any psychiatric symptom, from anxiety, to panic, to depression and even hallucinations and intrusive thoughts.
You can find vitamin B12 in dairy products, eggs, nutritional yeast, nori seaweed sheets and shitake mushrooms, but most vegans choose to supplement with Vitamin B12 as it is very difficult to get enough from diet alone.
What Hinders Vitamin B12 Absorption?
If you have a family history of pernicious anaemia, Coeliac disease, inflammatory bowel disease or Helicobacter pylori infection then you may find it harder to maintain your B12 level and you will need supplementation. Ideally blood levels of Vitamin B12 are over 600 to feel well. There are no known toxicity signs of taking too much vitamin B12, however some people can feel too energised from very high doses and this may affect sleep patterns. Some people need to take sublingual B12 under the tongue and others respond better to B12 injections which can be prescribed by your GP.
Omega-3 oil is critical for proper development of the brain, central nervous system and eyesight. Without enough we can become distracted and unfocused. Lack of omega 3 has also been implicated in developing depression and is even a risk factor for suicide risk.
Vegetarians can get omega 3 from organic whole milk and eggs, or omega 3 fortified eggs. Vegans can get it from walnuts, flax seeds, chia seeds, hemp seeds and cold pressed rape oil. However only a maximum of 10% of the plant-based omega 3 is converted into the useable DHA form that is so good for the brain. It is therefore important to top up with a good quality vegan Omega-3.
Choline is super important for the brain as it helps us to learn and maintain a good memory. Working memory is generally poor in those with dyslexia and ADHD. Peanut butter, tofu, sunflower seeds, beetroot and spinach naturally contain choline, and these are very important foods to eat regularly. Sunflower lecithin or ground sunflower seeds is a good way to boost up smoothies, porridge and baked foods such as muffins and pancakes.
Our gut flora also creates acetylcholine from lactobacillus, so working on the gut microbiome with live coconut kefir, miso, apple cider vinegar and sauerkraut can also give this a boost. You can also get vegan kefir powders to add to juices or smoothies.
Lectins are a family of carbohydrate-binding proteins and tend to be high in whole grains, legumes, potatoes, most cow’s milk (A2 cow’s milk and Guernsey milk is lectin-free) and fruit including tomatoes and bell peppers. If a person has compromised digestive enzyme production, then consuming excess lectins may lead to nutrient deficiencies and digestive problems. This is because the body cannot break down lectins and instead, they bind to nutrients and the cells lining the gastrointestinal tract.
Red kidney beans contain the most lectins and eaten raw can be toxic to humans – as few as four undercooked kidney beans can cause vomiting and diarrhoea. However, soaking and cooking the beans destroys all lectin toxicity and makes them safe to eat.
Lectins are most potent in their raw state. Therefore, cooking lectin-rich foods at high temperatures can dramatically reduce their content. Boiling or stewing legumes, for example, gets rid of almost all of the lectin content. Pressure cooking also destroys the lectins that naturally occur in beans. Soaking beans before cooking them is also effective. Okra, kiwi fruit and cranberry can block lectins, so it is good to incorporate these into your diet if you are sensitive to lectins. Supplements that contain bladderwrack and D Mannose may be helpful too.
As you can see, going plant-based does not only mean cutting back or eliminating animal products, it also needs a shift in the way you shop, prepare and cook your food. It’s when cooking from scratch and learning how to optimise your nutrition natural food ingredients could not be more important. It is possible to go plant-based and stay healthy, so incorporating these food preparation tips into your daily routine will help you do this with confidence.
- Dietary phytate, zinc and hidden zinc deficiency
- Implications of phytate in plant-based foods for iron and zinc bioavailability, setting dietary requirements, and formulating programs and policies
- Reduction of phytic acid and enhancement of bioavailable micronutrients in food grains
- NIH – Iron Fact Sheet for Health Professionals
- NIH – Calcium Fact Sheet for Health Professionals
- Do dietary lectins cause disease?
- Dietary Lectin exclusion: The next big food trend?