There are four vegan food groups: fruit, legumes, grains and vegetables. Vegans do not consume animal products, not only meat but also eggs, dairy products and other animal-derived substances. Vegan diets tend to be higher in dietary fibre, magnesium, folic acid, vitamin C, vitamin E, iron and phytochemicals and lower in dietary energy, saturated fat, cholesterol, long-chain omega-3 fatty acids, vitamin D, calcium, zinc and vitamin B12. That is why some nutrients are of great concern for vegans.
Vegans obtain all their protein from plants including:
- legumes – soy beans (consumed as tofu, tempeh, texturized vegetable protein, soy milk and edamame), peas, peanuts, black beans and chickpeas (the latter often eaten as hummus)
- grains – quinoa, brown rice, corn, barley, bulgur and wheat (mostly bread)
- nuts and seeds
Soy beans and quinoa are known as complete proteins because they each contain all the essential amino acids in amounts that meet human requirements.
Protein daily value is 50 grams.
Essential amino acids cannot be made by the body. As a result, they must come from food. The 9 essential amino acids are: histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine. Here is the optimal profile of the essential amino acids, which comprises complete protein:
- Tryptophan – 7mg/g of protein
- Threonine – 27mg/g of protein
- Isoleucine – 25mg/g of protein
- Leucine – 55mg/g of protein
- Lysine – 51mg/g of protein
- Methionine – 25mg/g of protein
- Phenylalanine – 47mg/g of protein
- Valine – 32mg/g of protein
- Histidine – 18mg/g of protein
Combinations that contain high amounts of all the essential amino acids include rice and beans, corn and beans, hummus and whole-wheat pita.
Vegans can maintain a high-protein diet. The only thing that they have to keep in mind it’s due to the lower protein density in plant-based foods they have to consume a larger absolute volume of food compared to a non-vegan diet. In fact, vegans must consume a lot more food to get a lot of protein. And when it comes to losing weight, protein is the king of nutrients. Period.
Our body cannot produce calcium, but the role this mineral plays is of vital importance. Actually, the role of calcium in our body is multifunctional: it makes our bones and teeth healthy and strong, our heart beat, our muscle function, our nerves transmit signals, and our hormones create. Ninety-nine percent of the body’s calcium is stored in the bones and teeth.
Vegans are advised to eat three servings a day of a high-calcium food, such as seaweeds, calcium-fortified soy milk and juice, calcium-set tofu, soybeans, almonds or hazelnuts, broccoli, collards, Chinese cabbage, kale, rocket, bok choy, mustard greens and parsley. The bioavailability of calcium in spinach is poor. Vegans should make sure they consume enough vitamin D, which is needed for calcium absorption.
We can get vitamin B12 only from animal sources. Vegans are unable in most cases to obtain B12 from their diet. A 2013 study found that “vegetarians develop B12 depletion or deficiency regardless of demographic characteristics, place of residency, age, or type of vegetarian diet. Vegetarians should thus take preventive measures to ensure adequate intake of this vitamin, including regular consumption of supplements containing B12” (https://www.ncbi.nlm.nih.gov/pubmed/23356638?dopt=Abstract)
Daily value of vitamin B12 is 2.4mcg (micrograms) for average adults. It is of utmost importance that vegans ensure they have an adequate intake of B12.
B12 is an exceptional, unique vitamin. This vitamin is of vital importance for us because it is involved in the metabolism of every cell of the human body. It plays a key role in the normal functioning of our brain and nervous system, the red blood cells formation, DNA synthesis, fatty acid and amino acid metabolism. No fungi, plants, animals or humans are capable of producing vitamin B12. Only bacteria and archaea have the enzymes needed for its synthesis. Animals must obtain vitamin B12 directly or indirectly from bacteria.
There are only two sources of vitamin B12 for vegans: foods fortified with this nutrient and supplements.
Although none of non-animal sources of vitamin B12 have been subjected to human trials, it is suggested that there is only one verified source of biologically active B12 – chlorella. Chlorella acquires B12 through a symbiotic relationship with heterotrophic bacteria, in which the bacteria supply B12 in exchange for fixed carbon.
A few words about chlorella
We’d like you to pay attention to chlorella – a great potential food source for vegans because it is high in protein and other essential nutrients that are hard to find in non-animal foods. Chlorella is fresh-water single-cell green algae, which is spherical in shape and about 2 to 10μm (micrometre) in diameter (to compare: a diameter of human hair is 50μm). Chlorella contains the green photosynthetic pigments chlorophyll-a and -b in its chloroplast. Through photosynthesis, it multiplies rapidly, requiring only carbon dioxide, water, sunlight, and a small amount of minerals to reproduce.
When dried, chlorella is about 45% protein, 20% fat, 20% carbohydrate, 5% fiber, and 10% minerals and vitamins. Mass-production methods are now being used to cultivate it in large artificial circular ponds. It is also abundant in calories and vitamins. Chlorella is consumed as a health supplement primarily in the United States and Canada and as a food supplement in Japan. Chlorella has a number of purported health effects, including an ability to treat cancer. However, according to the American Cancer Society, “available scientific studies do not support its effectiveness for preventing or treating cancer or any other disease in humans”. [https://en.wikipedia.org/wiki/Chlorella]
You can add chlorella to a variety of vegetarian smoothies.
OMEGA-3 FATTY ACIDS
Three omega-3 fatty acids play a crucial role in human physiology: alpha-linolenic acid (α-linolenic acid – ALA) comes from plant sources, and other two – eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) – come from animal sources. The health benefits of omega-3 fatty acids are mostly linked to EPA and DHA.
Omega-3 fatty acids are used differently in our body:
- EPA and DHA of animal origin are “ready-made” and can be utilized immediately.
- ALA of plant origin has to be converted in the body to EPA and DHA but the conversion rate is very low.
Vegans who are not supplementing have no intake of essential omega-3 EPA and DHA from their diet.