Plant-based diets and nutrition

Are you worried you’re not getting enough nutrients from a plant-based diet? Learn what nutrients you need, where to get them and what to monitor when eating a plant-based diet.

If you’re following a vegan, vegetarian or plant-based diet, it can be more challenging to meet the daily requirements of essential vitamins and minerals. But it’s certainly not impossible.

Do vegetarians and vegans need vitamin supplements?

According to the NHS, with good planning and understanding of what makes up a healthy balanced diet, you can get all the nutrients your body needs to be healthy, without the need for supplements [1].

As a vegetarian, make sure you’re getting enough:

  • Iron
  • Vitamin B12

As a vegan, make sure you’re getting enough:

  • Calcium
  • Iron
  • Vitamin B12
  • Omega-3 fatty acids

Plant-based sources of nutrients


Vitamin B12 is one of the only vitamins you cannot get naturally from plants alone, making it one of the most important nutrients for vegans to be aware of.

The body needs B12 to maintain healthy blood and a healthy nervous system [2]. Also known as cobalamin, vitamin B12 comes from a type of bacteria found in certain soils and the gastrointestinal tract of animals. According to our analysis of Medichecks’ customers, the mean active vitamin B12 level in vegans is 7% lower than in non-vegans.

Sources of B12 for vegans include:

  • Breakfast cereals fortified with B12
  • Unsweetened plant milk fortified with vitamin B12
  • Yeast extracts such as marmite or nutritional yeast, which are both fortified with vitamin B12

How much B12 do we need?

Adults aged 19 to 64 need about 1.5 micrograms a day of vitamin B12.

When there is a lack of vitamin B12, vitamin B12 deficiency anaemia may occur. This is because the lack of B12 can cause the body to produce abnormally large red blood cells that cannot function properly.

A B12 deficiency can lead to serious health problems if not treated with supplementation, including oral supplements in the form of sprays and tablets. In more serious cases, a doctor may administer B12 injections.

Symptoms of B12 deficiency:

  • Weakness or light-headedness
  • Tiredness
  • Heart palpitations or shortness of breath
  • Pale skin
  • A smooth tongue
  • Constipation, diarrhoea, and loss of appetite
  • Nerve problems like numbness or tingling, muscle weakness, and problems walking
  • Loss of vision
  • Depression, memory loss, or behavioural changes

If you are experiencing symptoms, or are concerned you may be deficient in B12, you can check your vitamin B12 levels with our simple finger-prick test.


Iron is an essential mineral that helps to transport oxygen throughout the body [3]. It is an important component of haemoglobin, the substance in red blood cells that carries oxygen from your lungs around the body. It is also necessary to maintain healthy cells, skin, hair, and nails.

Where do we get iron?

There are two forms of dietary iron: heme iron and non-heme iron.

Heme iron is in:

  • Meat
  • Poultry
  • Seafood
  • Fish

Non-heme iron is in plant foods like:

  • Grains
  • Beans
  • Vegetables
  • Fruits
  • Nuts
  • Seeds

Heme iron is easier to absorb than non-heme iron. So people who follow a plant-based diet must consume lots of vegetables that are high in iron.

Plant foods high in iron include:

  • Green vegetables, such as spinach, kale, and broccoli
  • Lentils and beans
  • Nuts and seeds
  • Grains such as whole-wheat pasta, brown rice, and fortified breakfast cereals
  • Dried fruit

Vitamin C can also help to enhance iron absorption. It captures non-heme iron and stores it in a form that is more easily absorbed by your body. So, drinking orange juice with your meal or squeezing some fresh lemon on your greens can increase your body’s absorption of iron [4].

How much iron do we need?

The amount of iron we need depends on age and gender. Women who have a healthy monthly period are at higher risk of iron deficiency and therefore need a higher amount of iron and may need to take iron supplements.

The recommended intake of iron for adults:

  • Males over 18 need 8.7mg a day
  • Females aged 19 to 50 need 14.8mg a day
  • Females aged 50+ need 8.7mg a day

When there is a lack of iron, iron deficiency anaemia may occur. Iron deficiency anaemia can lead to abnormally low levels of red blood cells. Without healthy red blood cells, your body can’t get enough oxygen. This can affect everything from brain function to the immune system.

Symptoms of iron deficiency:

  • Tiredness and lack of energy
  • Shortness of breath
  • Noticeable heartbeats (heart palpitations)
  • Pale skin

If your iron levels become low and you can’t improve them through diet alone, an iron supplement may be necessary.

Unlike some vitamins, you should be wary of an increased intake of iron, as too much can result in side effects such as nausea, diarrhoea, and vomiting. An Iron Blood Test that regularly monitors your iron levels can be helpful to make sure you are getting the right amount.

Vitamin D

Vitamin D is known as the sunshine vitamin. It is created in our bodies by the action of sunlight on our skin.

Vitamin D is crucial for regulating the amount of calcium and phosphate in the body, which keep bones, teeth, and muscles healthy.

Where do we get vitamin D? 

Vitamin D is found in a small number of foods, although it is difficult for our body to absorb enough from food alone.

We mainly get vitamin D from direct sunlight on our skin; around 15-20 minutes of midday sun exposure is recommended. But, from October to early March, we don’t get enough vitamin D in the UK from sunlight.

Throughout the winter in the UK, it is recommended to increase foods containing vitamin D, and the UK government recommends that all adults take a daily supplement during the winter months.

Sources of vitamin D include:

  • Fortified foods such as fat spreads, breakfast cereals, and tofu
  • Some mushrooms (portobello, maitake, button, and shitake)

How much vitamin D do we need?

From about late March/early April to the end of September, many people should be able to make all the vitamin D they need from sunlight on their skin.

Children over the age of one and adults need 10 micrograms of vitamin D a day [5].

Vitamin D deficiency is one of the most common deficiencies in the UK, affecting meat-eaters, vegans and vegetarians.

Symptoms of vitamin D deficiency include:

  • Getting sick or getting infections often
  • Tiredness and fatigue
  • Bone pain and loss
  • Depression
  • Impaired wound healing
  • Hair loss
  • Muscle pain

If left untreated, a lack of vitamin D can lead to bone deformities such as rickets in children and a bone condition called osteomalacia in adults [6].

A vegan diet will not necessarily impact vitamin D levels in the body, as most vitamin D comes from the sun, not the food we eat. So, vegans and meat-eaters alike need to ensure they get adequate amounts of vitamin D. The best way to do this is through a supplement in the form of a tablet or spray.

An easy way to monitor your vitamin D levels is by measuring them with a simple Vitamin D Blood Test.


Calcium keeps our bones and teeth strong and supports the nervous system, blood clotting, and muscle control.

Where can do we get calcium from?

Non-vegans get more of their calcium from dairy foods, so it’s important for non-vegans to get calcium from other foods.

Sources of calcium:

  • Fortified unsweetened soya, rice, and oat milk
  • Leafy green vegetables (but not spinach)
  • Almonds
  • Sesame seeds and tahini
  • Dried fruit
  • Pulses
  • Brown (wholemeal) and white bread

How much calcium do we need?

The recommended 700 milligrams of calcium per day can easily be met on a plant-based diet. The body also needs vitamin D to absorb calcium, which you can get either when exposed to sunshine or a small amount through fortified margarine and fat spreads, fortified breakfast cereals and egg yolks.

Omega 3 and 6

Fat is important for giving us energy and supporting cell growth. It also helps protect our organs, provides insulation, and helps us to absorb some nutrients and produce important hormones.

Omega-3 fats, or alpha-linoleic acid (ALA)m, and omega-6 fats, or linoleic acid (LA) are classed as essential because our bodies cannot make them. They are essential for our immune system, brain, nerves, and eyes.

Where do we get omega-3 and omega-6 fats?

Omega-3 fats are in:

  • Fatty fish like salmon, mackerel, anchovies, sardines, and trout
  • Flaxseeds and flaxseed oil
  • Walnuts
  • Soybeans
  • Tofu
  • Rapeseed oil
  • Fortified foods like eggs and some margarine, juices, and yogurts

Omega-6 fats are in:

  • Soybeans
  • Corn
  • Safflower and sunflower oils
  • Nuts and seeds
  • Meat, poultry, fish, and eggs

Other vitamins and nutrients and where to source them

Iodine - Your body uses iodine to make thyroid hormones. These hormones control how fast your cells work. In the UK, the recommended iodine intake for adults is 140 micrograms per day. Every vegan needs a reliable source of iodine in their diet. It can be found in plant foods, such as cereals and grain and seaweed. A non-seaweed supplement is arguably the most reliable way of meeting your body’s need for iodine. However, too much iodine can be dangerous as it can interfere with thyroid function. The NHS recommends taking 0.5mg or less a day of iodine supplements as this is unlikely to cause any harm.

Zinc - Zinc is an essential trace mineral. The body does not produce or store excess zinc so it must be consumed regularly as part of our diet. Only very small amounts are required in the body. Zinc is important for a healthy metabolism, a healthy immune system, wound healing, taste, and smell. For adults in the UK, recommended daily zinc intakes are 7mg (milligrams) for women and 9.5mg for men. It is possible to get all the zinc you need from eating a varied vegan diet and good sources of zinc include beans, chickpeas, lentils, tofu, walnuts, cashew nuts, chia seeds, ground linseed, hemp seeds, pumpkin seeds, wholemeal bread, and quinoa.

Selenium - Selenium is part of many important enzymes, which are substances that speed up reactions in our bodies. In the UK, recommended daily intakes of selenium for adults are 69 micrograms for women and 75 for men. It is important to avoid eating too much selenium as it can be toxic and cause a condition called selenosis. One of the best sources of selenium is brazil nuts. Alternatively, a supplement can be used to guarantee a reliable selenium intake.

Vitamin A - Vitamin A, also known as retinol, supports the immune system to work properly, helps with vision, and keeps the skin healthy. The amount of vitamin A adults aged 19 to 64 need is 0.7mg a day for men and 0.6mg a day for women. Though vitamin A is found mostly in animal products, our bodies can turn the antioxidant beta-carotene from plant foods into vitamin A. Good sources of beta-carotene can be found in yellow/orange, red, and green leafy vegetables such as spinach, carrots, sweet potatoes, and red peppers. It can also be found in yellow/orange fruit, such as mangoes, apricots, and cantaloupe.

Vitamin K – Vitamin K is essential for blood clotting and therefore wound healing. It is also needed to keep bones healthy and strong, and low levels have been associated with an increased risk of osteoporosis and arthritis. There are two types of vitamin K - K1 and K2. Vitamin K1 is found in leafy green vegetables such as kale, spinach, Swiss chard, parsley, romaine, and green leaf lettuce. It is also in vegetables such as Brussels sprouts, broccoli, cauliflower, and cabbage. One of the best sources of K2 is in the Japanese fermented soybean products natto and miso. Just as beta-carotene is converted into vitamin A in our bodies, bacteria in our gut can convert K1 from plants into K2, so it is possible to get adequate amounts of both K1 and K2 on a plant-based diet.


  1. 2022. Vegetarian and vegan diets Q&A. [online] Available at: <> [Accessed 4 March 2022].
  2. 2022. The vegan diet. [online] Available at: <> [Accessed 4 March 2022].
  3. 2022. Vitamins and minerals - B vitamins and folic acid. [online] Available at: <,vitamin%20B12%20from%20your%20diet.> [Accessed 4 March 2022].
  4. 2022. Vitamins and minerals - Iron. [online] Available at: <> [Accessed 4 March 2022].
  5. Hallberg L, Brune M, Rossander L. The role of vitamin C in iron absorption. Int J Vitam Nutr Res Suppl. 1989;30:103-8.
  6. 2022. Vitamin D. [online] Available at: <,aged%2011%20to%2017%20years.> [Accessed 4 March 2022].
  7. Sitta, M., Cassis, S., Horie, N., Moyses, R., Jorgetti, V. and Garcez-Leme, L., 2009. Osteomalacia and vitamin D deficiency in the elderly. Clinics, 64(2), pp.156-158.
  8. Kahleova, H., Fleeman, R., Hlozkova, A., Holubkov, R. and Barnard, N., 2018. A plant-based diet in overweight individuals in a 16-week randomized clinical trial: metabolic benefits of plant protein. Nutrition & Diabetes, 8(1).

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