Vegan Diets: Maintaining Optimal Vitamin Intake

A vegan diet can be a healthy, planet-friendly way to live, but it's important to ensure you're getting all the vitamins and minerals your body needs. Vegans don't eat any animal products, so it can be challenging to get enough of certain nutrients, such as vitamin B12, vitamin D, calcium, iron, and omega-3 fatty acids. Vitamin B12, for example, is mostly found in animal sources, so vegans may need to include fortified foods like nutritional yeast or supplements in their diet to meet their daily requirements. Similarly, vitamin D is mostly obtained from sunlight, but in winter, it can be challenging to get enough, and vegans may need to rely on fortified foods or supplements. Calcium, which is important for bone health, is also more easily absorbed from animal sources, so vegans may need to be mindful of including calcium-rich plant foods like leafy greens and fortified plant-based milk in their diet. Iron and omega-3 fatty acids are also important nutrients that vegans may need to focus on, as plant-based sources are not always sufficient to meet the body's needs. Overall, a well-planned vegan diet that includes a variety of whole foods and some fortified options can provide most of the necessary nutrients, but supplementation may be necessary in some cases.

Vitamin B12

Vegans can get vitamin B12 from fortified foods such as breakfast cereals, nutritional yeast (but only when fortified), and plant-based milk alternatives like soya and almond milk. Yeast spreads like Marmite are also a good source of vitamin B12 for vegans. However, these sources may not be reliable, and vitamin B12 is best absorbed in small doses, so a daily supplement containing 25-100 mcg of cyanocobalamin or a weekly dosage of 2,000 mcg is recommended.

It is important to note that vitamin B12 is light-sensitive and may degrade if stored in clear plastic bags. As the ability to absorb vitamin B12 decreases with age, the Institute of Medicine recommends that everyone over the age of 51—vegan or not—consider taking a supplement or consuming fortified foods.

Vitamin D

For those who cannot rely on sun exposure, vitamin D can be obtained through diet and supplements. However, very few foods naturally contain vitamin D, and even fortified foods may not provide sufficient amounts to meet daily requirements. Good dietary sources of vitamin D for vegans include fortified foods such as fat spreads, breakfast cereals, and unsweetened soya drinks. Some plant-based milk alternatives like rice, oat, soy, and almond milk are also fortified with vitamin D, but they only provide very low levels.

Calcium

Vegan sources of calcium include:

• Fortified plant-based milk alternatives such as soya, pea, oat, and coconut milk. Always check the labels, as not all brands are fortified.
• Fortified plant-based yoghurt alternatives, such as plain soya yoghurt and coconut yoghurt.
• Green, leafy vegetables like broccoli, cabbage, kale, watercress, mustard greens, turnip greens, and okra. Spinach is also a green, leafy vegetable that contains high levels of calcium, but the body cannot digest it all.
• Fortified foods such as soya and linseed bread, ready oat cereal, and unsweetened soya drinks.
• Dried fruit, including raisins, prunes, figs, and dried apricots.
• Nuts and seeds, including sesame seeds, tahini, almonds, sunflower seeds, and pumpkin seeds.
• Tofu, especially if it is calcium-set or processed with calcium sulphate.

It is worth noting that we tend to absorb less calcium from plant sources than from dairy or other animal foods due to natural compounds like oxalates and phytates, which reduce our ability to access calcium. Therefore, it is important to include a variety of calcium-rich and fortified foods in your diet and consider taking a calcium supplement if you are not getting enough from your diet.

The recommended daily intake of calcium for adults is 1000 mg per day, but this varies depending on age and gender. For example, women over 51 and men over 70 are recommended to aim for 1200 mg per day.

Iron

A common misconception is that a vegan diet lacks iron. However, this is not true. Vegans can get enough iron from plant-based sources, and they are no more likely to develop iron deficiency anemia than the general population. In fact, vegans typically consume adequate amounts of iron because their diet is often rich in vitamin C, which improves the absorption of non-heme iron.

Include Iron-Rich Plant Foods

Vegans can obtain non-heme iron from a variety of plant-based sources, including:

• Dried beans and legumes (e.g., lentils, kidney beans, soybeans)
• Dark green leafy vegetables (e.g., spinach, Swiss chard, kale)
• Dried fruits (e.g., apricots, prunes, figs, raisins)
• Nuts and seeds (e.g., pumpkin seeds, sesame seeds, tahini)
• Wholegrain cereals and breads
• Fortified plant-based milk, such as soy milk

Enhance Absorption with Vitamin C

Vitamin C increases the absorption of iron. Pair iron-rich foods with vitamin C-rich foods, such as bell peppers, broccoli, oranges, strawberries, or kiwis. For example, you can add bell peppers to a hummus and bean wrap or have a glass of orange juice with a meal.

Avoid Inhibitors of Iron Absorption

Certain compounds can reduce iron absorption. Tea, coffee, and phytates found in unrefined grains, seeds, and pulses can inhibit iron absorption. It may be helpful to avoid consuming tea or coffee with meals and to soak and sprout pulses to reduce phytates.

Cook with Cast Iron Pans

Cooking with cast iron pans can be beneficial as a small amount of iron may be transferred to the food during the cooking process.

Consider Iron Supplements

While it is possible to obtain adequate iron from a well-planned vegan diet, some individuals may benefit from taking an iron supplement. This is particularly important for women with heavy menstrual bleeding, as they are at a higher risk of iron deficiency anemia. However, it is always recommended to consult with a healthcare professional before taking any supplements.

Omega-3 fatty acids

The plant-derived omega-3, alpha-linolenic acid (ALA), is the only essential omega-3 fatty acid. Our bodies cannot produce it, so we must consume it through our diets. ALA is found in high amounts in walnuts, flaxseed, chia seeds, hemp seeds, and soybeans. The body converts ALA into the longer-chain omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). EPA and DHA are important for brain health and can be obtained directly from the diet by eating fish. However, the body can also convert ALA into these longer-chain omega-3s.

While it is possible for vegans to get sufficient omega-3s by consuming ALA-rich plant foods, it is important to note that the conversion rate of ALA to EPA and DHA is relatively low. Studies estimate that only about 5-10% of ALA is converted to EPA, while less than 0.5% is converted to DHA. As a result, vegans may benefit from supplementing with EPA and DHA derived from algae oil. Algal oil supplements are typically available in softgel form and can also be added to drinks or smoothies.

In addition to ensuring adequate intake of omega-3 fatty acids, it is important to maintain a balanced ratio of omega-6 to omega-3 fatty acids. A diet low in omega-3s but high in omega-6s can increase inflammation and the risk of disease. Oils such as corn, safflower, sunflower, and sesame oils are high in omega-6 fatty acids, so it is recommended to minimise their intake and prioritise consuming ALA-rich foods to maximise EPA and DHA levels.

• Sprinkle ground linseed (flaxseed) or shelled hemp seeds on overnight oats, porridge, or breakfast cereal.
• Stir chia seeds into some fortified yoghurt.
• Use walnuts to add flavour and texture to a salad or press them into peanut butter on toast.
• Blend walnut, linseed (flaxseed), or hemp oils into dips or use them to make salad dressings.

Frequently asked questions