Meeting all your nutrient requirements on a plant-based diet


Veganuary is a growing trend with more people adopting a vegan diet every January. Eating a variety of plant-based foods can have many benefits, choosing different colour fruit and vegetables can help you to do this. However, you do not have to eat an exclusively plant-based diet (vegan or vegetarian) to reap the health benefits of plant-based foods. 

Plant-based diets can be very high in fibre. Many people with gut problems, like IBS, may find it difficult to digest large amounts of fibre. Too much fibre can result in bloating, flatulence, abdominal cramps and sometimes diarrhoea. More information on this can be found in our previous blogs titled ‘Does an exclusively plant-based diet make sense if you have a gut condition?’ and ‘Is Veganuary good for your gut? Should you do it if you have a gut condition?’

It is possible to meet all of your nutritional requirements on a well-planned vegan diet. However, this is more difficult for those with gut issues as many of the foods which vegans rely on to meet their nutritional needs e.g. beans, peas and lentils are not well tolerated by those with gut issues.

How to meet your protein requirements on a plant-based diet

Protein is essential for growth, repair, immune function and much more. Those consuming a plant-based diet usually rely heavily on beans, peas and lentils for their protein intake. Canned, rinsed and well-drained versions of these are better tolerated than when cooked from dry. We recommended trailing smaller portions and gradually increasing your intake to find your tolerance. Alpha-galactosidase enzymes may be taken to help digest legumes.

However, those with gut problems often struggle to digest these pulses making it more difficult to meet their protein requirements. Firm tofu, tempeh, quorn, nuts, nut butter, seeds, spirulina and pea protein are good options for those with gut issues who are trying to increase their plant-based protein intake.

How to meet your calcium requirements on a plant-based diet

Calcium is needed for strong bones and teeth, regulating muscle contractions and normal blood clotting. It can be challenging to meet calcium requirements on a vegan diet due to the restriction of dairy products.

Plant-based sources of calcium include almonds, calcium-set tofu, broccoli, soya beans, spinach, orange and tahini. Products with calcium added – known as fortified products also provide an important source of calcium. Check the labels of your plant-based dairy alternatives to make sure they are fortified with calcium.

To meet calcium requirements of 800mg a day, on a vegan diet, you would need to eat three tablespoons of tahini, three cereal bowls of kale, three cereal bowls of spinach and 45 almonds! You should be careful about eating this amount of fibre if you have gut problems, as it will probably trigger your gut symptoms.

How to meet your iron requirements on a plant-based diet

Iron is needed to produce haemoglobin – a protein that carries oxygen around the body, for cell growth, producing red blood cells, producing certain hormones, a healthy immune system and infant growth and development.

Too little iron can lead to iron deficiency anaemia. The National Adult Nutrition Survey in Ireland saw that 48% of women aged 18-64, and 17% of women over 65 years old had inadequate iron intake. Iron deficiency is more common in women due to periods and pregnancy.

There are two types of iron, heme iron; found in animal foods, which is easily absorbed by the body. And non-haem iron, found in plant foods such as grains, legumes, beans, nuts and seeds, which is not easily absorbed by the body.

To meet the upper end of iron requirements, 14mg a day, on a vegan diet you would need to eat 180g of lentils, 3 bowls of kale and 2 heads of broccoli. The large amount of fibre and the fermentable component of lentils may lead to gut symptoms. Iron-fortified cereals may help you to meet your iron requirements if you have gut problems.

The absorption of non-haem iron is reduced by tannins founds in tea and phytates found in bran-containing cereals. Avoid consuming plant-based iron with tannin or phytate-containing foods. While absorption is increased by vitamin C- found in oranges, peppers, tomatoes etc. Combine plant-based iron with a source of vitamin C to increase its absorption e.g. lentils cooked in tomato source.

Gut problems including IBD and coeliac disease increase the risk of iron deficiency anaemia. There are several reasons for this including increased blood loss due to intestinal bleeding and reduced absorption due to inflammation or removal of part of the gut. If you have one of these conditions talk to your GP about getting a blood test for iron deficiency anaemia. You may need a supplement to help you restore your iron levels.

How to meet your B12 requirements on a plant-based diet

B12 is a micronutrient predominantly found in animal products including meat, milk, and eggs. Nutritional yeast and fortified products provide vegan diets with a small amount of B12. However, it is difficult to meet B12 requirements on an exclusively plant-based diet. A daily 10mg or weekly 2000mg B12 supplement is recommended for vegans.

B12 is absorbed in a part of your gut called your terminal ileum. Inflammation can occur here with IBD or coeliac disease meaning that B12 is not properly absorbed. If you have IBD you should have your B12 levels checked regularly. If you are not absorbing B12 properly you will need to get B12 injections from your doctor.

Lifelong B12 injections are also needed if you have had more than 20cm of your distal ileum (part of your bowel) removed regardless of your B12 intake (ESPEN 2020).

How to meet your omega-3 fatty acid requirements on a plant-based diet

Omega-3 fatty acids are a type of fat, they are known to have anti-inflammatory properties. Seafood is the main dietary source of omega-3 fatty acids.

The anti-inflammatory properties of omega-3 fatty acids help protect our lungs, heart, blood vessels and brain. The international organization for the study of IBD (IOIBD) recommends increased consumption of omega-3 fatty acids from fish e.g. mackerel, salmon, and sardines for ulcerative colitis patients.

There are 3 types of omega-3 fatty acids: alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). DHA and EPA are more readily absorbed by the body. Therefore they have greater health-promoting benefits than ALA. DHA and EPA are only found in seafood and microalgae. Therefore EPA and DHA intake is often very low in those consuming an exclusively plant-based diet.

Plant-based sources of ALA include flaxseed, walnuts, hempseed, rapeseed, chia seed, soybean, wheat germ, and their oil derivatives and some leafy green vegetables. However, only a small amount of ALA is converted into EPA (5-10%) and DHA (2-5%).

Those on an exclusively plant-based diet should consider taking a microalgae omega-3 supplement to meet their EPA and DHA requirements.

How to meet your iodine requirements on a plant-based diet

Iodine is needed for healthy thyroid function and metabolism. Iodine is usually found in dairy products and seafood. Therefore it is difficult to meet your iodine requirements on an exclusively plant-based diet.

Seaweed is a plant-based source of iodine however eating too much iodine can have negative effects so seaweed should only be consumed once a week. Many dairy alternatives are fortified with iodine. You may need an iodine supplement if you are consuming a plant-based diet.

Take home message

Plant-based foods have many health benefits however you do not need to eat an exclusively plant-based diet to experience the benefit of plant-based foods.

If you have a gut condition you may be better off consuming a Mediterranean- based diet that is rich in plant foods while also incorporating some fish and dairy along with occasional meat intake.

If you have a gut condition and you are increasing your intake of plant-based foods you should find your individual tolerance to these foods as well as your personal fibre tolerance.

Our book What Every Woman Needs To Know About Her Gut can help you to find your tolerance to fermentable foods and help you to minimise your gut symptoms.

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