Vegan Diet: Suboptimal For Fitness Goals

Veganism has been associated with adverse health outcomes, such as nervous, skeletal, and immune system impairments, hematological disorders, and mental health problems due to the potential for micro and macronutrient deficits.

Vegans have a greater prevalence of mental health problems, which may lead to a poorer quality of life. An optimal diet should be balanced, consisting of lean meat, nuts, fresh fruits and vegetables, and olive oil.

However, numerous studies have demonstrated that eating a diet rich in plants is better for our general health, with a strong correlation to reducing the incidence of chronic diseases. A plant-based diet is endorsed by national health bodies, including the Australian Government’s Dietary Guidelines, Dietitians Australia, and the Academy of Nutrition and Dietetics.

It is important to note that vegans often have better socioeconomic levels, live a healthier lifestyle with more physical exercise, and tend to smoke less compared to non-vegetarians, making it difficult to isolate the effects of veganism in observational research.

Lack of vitamin B12

Vitamin B12 is essential for cell growth and a healthy nervous system. A deficiency in vitamin B12 can lead to neurological and haematological problems, such as pernicious anaemia and megaloblastic anaemia with demyelination of the central nervous system. Vitamin B12 is not produced by plants, but by microorganisms that live in symbiosis with many plants. Vegans must therefore ensure they are consuming enough vitamin B12 through supplements or fortified foods.

The human body only absorbs a tiny amount of B12 each time it is consumed. For this reason, it is recommended that vegans adopt one of the following strategies for optimal consumption:

• Two daily servings of fortified foods, providing 1.5 to 2.5 micrograms each.
• One daily supplement of at least 25 micrograms.
• One supplement of 1,000 micrograms twice weekly.

The human body's ability to absorb B12 decreases with age. For this reason, dietitian Dr Amanda Benham recommends that those over 50, whether vegan or not, take a B12 supplement.

Higher risk of stroke

A vegan diet is often associated with improved health outcomes and a reduced risk of cardiometabolic diseases, such as cardiovascular disease, type 2 diabetes, obesity, and non-alcoholic fatty liver disease. However, a study published in the medical journal The BMJ has raised concerns about a potential link between vegan diets and an increased risk of stroke.

The study, conducted by researchers in the United Kingdom, analyzed the risk of stroke and other health issues over two decades among nearly 50,000 people based on their dietary patterns. The results indicated that compared to meat-eaters, vegetarians had a 20% higher risk of stroke, equivalent to three extra cases per 1,000 people over ten years. This elevated risk was primarily attributed to hemorrhagic stroke, which involves bleeding into the brain.

It is important to note that the overall risk of stroke among vegetarians was still relatively small, and the study had several limitations. For example, it was an observational study, which means it only observed the relationship between diet and health outcomes without establishing causation. Additionally, the study population may not be representative of all vegetarians, and self-reported dietary data may not always be accurate.

Further research is needed to confirm these findings and understand the underlying mechanisms. In the meantime, it is crucial for vegans and vegetarians to ensure they are meeting their nutritional requirements, especially for vitamin B12 and omega-3 fatty acids, which are essential for maintaining a healthy nervous system and reducing the risk of cardiovascular disease.

While a well-planned vegan diet can be nutritionally adequate and offer health benefits, it is important to be mindful of potential risks and ensure a balanced intake of essential nutrients.

Inadequate protein intake

Protein is essential for muscle growth and repair, and it is well known that a vegan diet can make it more challenging to meet protein requirements. This is because animal proteins are considered complete proteins and have a higher biological value, protein efficiency ratio, net protein utilization, and Protein Digestibility Corrected Amino Acid Score (PDCAAS) than plant proteins.

Plant vs animal protein

Plant proteins are generally less digestible (50-70%) than animal proteins, and food processing methods like heating can further reduce digestibility. However, it is important to note that some plant sources, such as soy, contain all the essential amino acids and can be a good source of protein for vegans. Other plant sources of protein include legumes, seeds, nuts, grains, and vegetables.

Protein requirements

Protein requirements for vegans are often 10-20% higher than for non-vegans. For example, the recommended protein intake for vegan strength athletes is 1.8-2.2 g per kg of body weight, compared to 1.6-2.0 g per kg for non-vegans. It is important to distribute protein intake evenly throughout the day, aiming for 0.40-0.55 g/kg per meal, including within 1-2 hours of pre- and post-training.

Meeting protein requirements

To ensure adequate protein intake on a vegan diet, it is crucial to include a variety of protein sources, such as legumes, beans, chickpeas, tofu, tempeh, quinoa, grains, nuts, seeds, and dark green leafy vegetables. Additionally, supplementing with a reliable source of vitamin B12 is recommended, as it plays an important role in protein metabolism and overall health.

Potential health consequences of inadequate protein intake

In summary, while it is possible to meet protein requirements on a vegan diet, it requires careful planning and may be more challenging than on a non-vegan diet due to the lower digestibility and biological value of plant proteins.

Increased risk of mental health issues

Vegan diets have been associated with adverse health outcomes, including nervous, skeletal, and immune system impairments, hematological disorders, and mental health problems. Research has shown that vegans have a greater prevalence of mental health problems, which may lead to a poorer quality of life.

One study found that meat-free diets were linked to worse psychological health, with higher rates of unipolar depressive and anxiety disorders. Another study found that vegan mothers may have poor prenatal nutritional status, resulting in low maternal fat reserves for breastfeeding. This can lead to a decline in the postpartum nutritional profile of the mother, which is essential for infant development.

Additionally, vitamin B12 deficiency, which is common in vegan diets due to the exclusion of vitamin B12-rich foods, has been linked to neurological problems.

Therefore, it is crucial for vegans to monitor their nutritional intake and supplement their diets as needed to mitigate any potential negative impacts on their mental health.

Calcium deficiency

Calcium is a crucial mineral for the body, playing a role in muscle contraction, blood pressure regulation, nerve transmission, and blood clotting. The recommended daily intake of calcium is 1,300 mg, but a large percentage of people do not meet these recommendations, including vegans.

Vegan diets are often associated with lower calcium intakes, which can lead to a deficiency. This is primarily due to the exclusion of dairy products, which are typically rich in calcium. However, it is important to note that dairy is not the only source of calcium, and there are plenty of plant-based options available.

Soybeans and Soy Products

Soybeans are naturally rich in calcium, providing about 13% of the daily value (DV) per 172 grams. Tofu, tempeh, and natto, which are made from soybeans, are also excellent sources. Tofu made with calcium sulfate can provide up to 53% of the DV per 3.5 ounces. Tempeh and natto, which are made from fermented soybeans, offer around 7% of the DV per 3.5 ounces.

Beans, Peas, and Lentils

In addition to being rich in fiber and protein, beans and lentils are good sources of calcium. Some varieties that provide higher levels of calcium per cooked cup include white beans, pinto beans, kidney beans, and chickpeas. They also tend to be rich in other nutrients like iron, zinc, potassium, magnesium, and folate. Soaking, sprouting, and fermenting beans and lentils can reduce antinutrient levels and enhance their absorbability.

Nuts

All nuts contain calcium, but almonds are particularly rich, providing 96 mg per 1/4 cup, which is about 10% of the DV. Brazil nuts are the second-best option, offering around 4% of the DV per 1/4 cup. Nuts are also good sources of fiber, healthy fats, protein, antioxidants, and various vitamins and minerals. Regular nut consumption may aid weight loss, lower blood pressure, and reduce risk factors for metabolic diseases like type 2 diabetes and heart disease.

Seeds and Their Butters

Seeds and seed butters are also good sources of calcium, with the amount varying by variety. Tahini, a butter made from sesame seeds, is one of the best options, providing 10% of the DV per 2 tablespoons. Chia seeds are another good choice, offering around 14% of the DV per ounce. Like nuts, seeds provide fiber, protein, healthy fats, vitamins, minerals, and beneficial plant compounds. They are also linked to reduced inflammation, blood sugar levels, and risk factors for heart disease.

Grains

Some varieties of grains, such as amaranth and teff, provide around 9% of the DV per cooked cup. These gluten-free ancient grains can be incorporated into various dishes. Amaranth can be used as a substitute for rice or couscous, while teff can be made into porridge or added to chili. They can also be ground into flour and used to thicken soups and sauces.

Seaweed

Adding seaweed to your diet is another way to boost your calcium intake. Wakame, a variety typically eaten raw, provides around 9% of the DV per cup. Kelp, which can be eaten raw or dried, is another option. A cup of raw kelp added to salads or main dishes provides around 10% of the DV. 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.

Certain Vegetables and Leafy Greens

Some vegetables, especially bitter ones like dark leafy greens and cruciferous vegetables, are rich in calcium. Spinach, turnip greens, mustard greens, and collard greens provide 6-13% of the DV per cooked 1/2 cup. However, these vegetables also contain variable levels of antinutrients like oxalates, which can bind to calcium in the gut and reduce its absorption. Low- and moderate-oxalate vegetables like turnip greens, broccoli, and kale are better sources of absorbable calcium. Boiling these vegetables can reduce oxalate levels by 30-87%, making it easier for your body to absorb calcium.

Fruits

Some fruits contain good amounts of calcium. Raw figs provide close to 1% of the DV per fig, while dried figs offer slightly less. Oranges are another calcium-rich fruit, with one navel orange containing around 5% of the DV. Blackcurrants, blackberries, and raspberries are also decent sources, providing around 4-5% of the DV per cup. In addition to calcium, these fruits offer fiber, vitamin C, and other essential vitamins and minerals.

Fortified Foods and Drinks

Fortified foods and drinks are another way to increase your calcium intake. Some examples include plant yogurts, certain types of cereal, flour, cornmeal, and baked goods like bread, crackers, or tortillas. Fortified drinks, such as plant milks and orange juice, can also provide significant amounts of calcium. For example, 1 cup of fortified orange juice can provide up to 28% of your daily calcium requirements. Soy milk, in particular, is a great alternative to cow's milk, as it contains a similar amount of protein. Just make sure to check the label, as not all plant milks are fortified.

Blackstrap Molasses

Blackstrap molasses is a sweetener that also provides a nutritional punch. It is made from sugar cane that has been boiled three times and contains several vitamins and minerals, including 15% of the DV of calcium per tablespoon. However, it is high in sugar, so it should be consumed in moderation.

While it is important to ensure adequate calcium intake, it is also worth noting that calcium supplements can be considered if dietary sources alone are insufficient. Calcium supplements of 1,000 mg per day generally appear safe for healthy individuals, but those with chronic kidney disease should consult their physicians before taking them.

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