Vegan Diets: What Nutrients Are Missing?

A vegan diet is a plant-based diet free from animal products, including meat, seafood, dairy, eggs, and honey. While veganism can be an ethical choice, it is important to consider the nutritional implications of eliminating animal products from your diet.

Vegan diets can be healthy and nutritious, but they may also lack certain key nutrients that are typically found in animal products. Here are some of the nutrients that may be lacking in a vegan diet:

- Protein is essential for metabolism and tissue growth and repair. Animal sources of protein, such as fish, eggs, and meat, contain all nine essential amino acids, while most plant-based sources only contain a few. To get all the essential amino acids, vegans should eat a variety of plant-based foods and consider including soy, quinoa, and mycoprotein in their diet.

- Vitamin B12 is important for nervous system function and red blood cell production. It is naturally found in animal products, and a deficiency can lead to anemia. Vegans can get vitamin B12 from fortified foods or supplements.

- Iron is essential for producing hemoglobin, which transports oxygen in the blood. The body absorbs iron from animal sources (haem iron) more easily than from plant sources (non-haem iron). However, consuming vitamin C along with non-haem iron can improve its absorption.

- Calcium is essential for bone and dental health and is mainly found in dairy products. Vegans can get calcium from broccoli, fortified plant-based milk, fortified flour, and tofu.

- Vitamin D is essential for calcium absorption and healthy bones and teeth. It can be obtained through exposure to sunlight or from dietary sources like egg yolks, fatty fish, and fortified foods. Vegans may need to take supplements, especially during winter or in regions with limited sunlight.

- Omega-3 fatty acids are important for heart health and can be found in fatty fish. Vegans can get omega-3 fatty acids from plant sources like linseeds, chia seeds, hemp, and walnuts, but the conversion to a form usable by the body is inefficient.

- Iodine is important for thyroid function and is found in fish and shellfish. Vegans can get iodine from fortified plant-based products, but the iodine content in vegetables varies depending on the soil they are grown in.

Protein

The amount of protein we need depends on several factors, including age, sex, weight, and physical activity. The Dietary Guidelines for Americans (DGA) recommends a daily intake of 0.8 grams of protein per kilogram of body mass. However, this may vary depending on activity levels. For example, strength athletes may require up to 1.7 grams of protein per kilogram of body mass per day.

There is a common misconception that vegan diets lack sufficient protein. However, this is not the case, as vegans can get protein from various plant sources. Some of the best sources of plant-based protein include:

• Seitan
• Soybeans and soy products (tofu, tempeh, edamame)
• Legumes (beans, lentils, chickpeas)
• Nuts and nut butter
• Seeds (quinoa, chia seeds, hemp seeds)
• Grains (oats, wild rice, bulgur)
• Vegetables (broccoli, spinach, asparagus, artichokes, potatoes, sweet potatoes, Brussels sprouts)

Complete Proteins

A complete protein is a food that contains all nine essential amino acids. Most complete protein sources are animal-based, such as meat, fish, eggs, and dairy. However, there are some plant-based complete proteins, including quinoa, chia seeds, and soy products.

Combining Plant Proteins

It is a myth that vegans need to carefully combine specific plant foods at each meal to ensure they get all the essential amino acids. While it is important to eat a variety of plant-based proteins, it is not necessary to get all nine essential amino acids at every meal. As long as you consume a variety of plant proteins throughout the day, your body will break down and combine the amino acids to form complete proteins.

Health Considerations

While it is possible to get enough protein on a vegan diet, there are a few health considerations to keep in mind:

• Variety is key: Eating a variety of plant-based proteins ensures you get all the essential amino acids and improves the overall quality of your diet.
• Processed foods: Relying heavily on processed vegan foods may result in a lack of variety in the diet and insufficient intake of fruits, vegetables, and whole grains.
• Bioavailability: The digestibility of plant proteins may be lower than that of animal proteins due to the presence of anti-nutritional compounds and an unbalanced amino acid composition. Combining different plant protein sources and incorporating gentle food processing techniques can help improve the bioavailability of plant proteins.
• Individual needs: Some individuals, such as athletes or those with certain health conditions, may have higher protein requirements. It is always best to consult with a healthcare professional to ensure your dietary needs are being met.

In conclusion, while it is possible to get enough protein on a vegan diet, it is important to include a variety of plant-based protein sources and ensure your diet is well-planned and includes minimally processed whole foods.

Vitamin B12

Vegans need to be mindful of their vitamin B12 intake as it is not abundantly available in plant-based sources. Some plant-based milk and breakfast cereals are fortified with vitamin B12, but the daily recommended amount of 1.5 micrograms can be tricky to achieve without supplementation.

Recently, research by scientists at Cambridge University has highlighted the potential of algae as a natural source of vitamin B12 for vegans. Algae, being aquatic organisms without roots or stems, have shown a remarkable ability to accumulate B12. This discovery could lead to the development of effective algal-based supplements to address the issue of B12 deficiency in vegan diets.

In conclusion, while vitamin B12 is essential for overall health, vegans may struggle to obtain sufficient amounts from plant-based sources alone. Fortified foods and supplements can help bridge this gap, but it is important to be mindful of the form of B12 and its effectiveness. The development of algal-based supplements shows promise in providing a natural and efficient solution for vegans to meet their vitamin B12 needs.

Iron

There are two types of iron: heme iron, which comes from animal sources, and non-heme iron, which comes from plant sources. Heme iron is more readily absorbed by the body than non-heme iron. However, vegans can still get enough iron by consuming a variety of plant-based sources of non-heme iron, such as:

• Dried beans and legumes
• Dark green leafy vegetables (e.g. spinach, kale)
• Dried fruits
• Nuts and seeds
• Wholegrain cereals and breads
• Iron-fortified products (e.g. tofu, tempeh, breakfast cereals)

In addition, the absorption of non-heme iron can be improved by consuming vitamin C at the same time. For example, squeezing lemon juice over a dish or having a glass of orange juice with a meal. On the other hand, consuming caffeine alongside non-heme iron can prevent its absorption.

It is important to ensure adequate iron intake, as iron deficiency can lead to anaemia, causing symptoms such as dizziness, fatigue, and pale skin. However, it is also possible to get too much iron, so finding the right balance is important.

Calcium

The average adult needs roughly 1,000 milligrams of calcium per day. For women over 50 and men over 71, that amount increases to 1,200 milligrams per day. Vitamin D is necessary for the absorption of calcium, and some foods like orange juice, milk, and breakfast cereals are fortified with calcium and vitamin D.

While dairy products are often promoted for their calcium content, an abundance of plant-based foods are also high in calcium. Calcium-rich plant-based foods include tofu, fortified nut milks, beans, kale, tahini, sweet potatoes, watercress, okra, chia seeds, and almonds.

Some of the best vegan sources of calcium include:

• Almonds, which provide 75 milligrams per 30-gram serving (about 20 almonds). Hazelnuts and tahini also contain decent amounts.
• Amaranth, a gluten-free ancient grain that provides 80 grams of calcium per one-quarter cup (dry). It can be used as a substitute for rice or couscous.
• White beans (navy beans), kidney beans, and chickpeas. Navy beans top the list with 132 milligrams of calcium per cup, followed by kidney beans and chickpeas with 93 and 99 milligrams, respectively.
• Minimally processed soy foods like tofu, tempeh, and edamame. Tofu made with calcium sulfate provides 683 mg, or 53% of the daily recommended amount, per 3.5 ounces (100 grams).
• Blackstrap molasses, a sweetener made from sugar cane that has been boiled three times. It contains 191 mg of calcium, or 15% of the daily recommended amount, per tablespoon. However, it is very high in sugar, so it should be consumed in moderation.
• Dark leafy greens like broccoli, kale, collard greens, and bok choy. A cup of cooked broccoli provides 112 milligrams of calcium, while spinach, turnip, mustard, and collard greens offer 164 mg per cooked 1/2 cup.
• Seaweed, such as wakame and kelp, can also provide calcium. However, seaweed may contain high levels of heavy metals and excessive amounts of iodine, so it should not be consumed too often or in large quantities.
• Fortified foods and drinks, such as plant yogurts, cereals, flour, cornmeal, plant milks, and orange juice. Fortified orange juice can provide up to 28% of the daily recommended amount of calcium.

Vitamin D

• Weakened immune system
• Fatigue
• Depression
• Bone and back pain
• Impaired wound healing
• Hair loss

Vegan Sources of Vitamin D

Since many of the foods highest in vitamin D are animal-based, such as salmon, egg yolks, and shellfish, it can be challenging for vegans to get enough vitamin D. However, there are some good vegan sources of vitamin D:

• Fortified foods: Soy milk, rice milk, almond milk, orange juice, breakfast cereals, and oatmeal are often fortified with vitamin D. It is important to check the labels to see if vitamin D has been added, as the amount can vary between brands.
• Mushrooms: Mushrooms are one of the only non-animal sources of vitamin D. Those exposed to ultraviolet light when growing may contain higher amounts.
• Sunlight: Spending time in the sun is a great way for vegans to boost their vitamin D levels. Most people need about 10 to 30 minutes of sun exposure three times a week, but those with darker skin may require more time in the sun.

Frequently asked questions