Many studies have highlighted nutritional deficiencies in vegan people. However, they are mostly attributable to an incorrect application of the vegan diet. Scientific research has now shown that it represents a safe approach in all phases of life and a valid ally in the prevention of chronic diseases. However, for a vegan food approach to be safe, it must be balanced in all its nutrients.
Vegans exclude all foods of animal origin from their diet, for ethical and / or health reasons. Specifically, a person who embraces this food style eliminates meat, fish, eggs, honey, dairy products and its derivatives from their meals. Often, being vegan is not confined only to eating habits but extends to lifestyle, trying to minimize the impact of man on the environment.
Vegan diets have been demonized for a long time because they are considered incapable of satisfying all human nutritional needs. Many studies have indeed highlighted deficiencies in vegan people. However, these are mostly attributable not to the lifestyle itself but to its incorrect application. The diets of these subjects tend to be unbalanced on some macronutrients and micronutrients, causing serious deficiencies in the body.
The aspects to keep in mind, in terms of macronutrients, when deciding to follow a vegan diet, are the following:
- Do not tilt the diet towards carbohydrates. A diet must respect a correct distribution of all macronutrients (carbohydrates, proteins and lipids), even if this requires a great deal of effort compared to a non-vegan approach. Vegans must also be careful not to exceed the amount of fiber intake, which could cause gastrointestinal problems, diarrhea and dehydration, as well as limiting the absorption of some micronutrients, such as calcium and zinc;
- We recommend a higher protein intake than that of the omnivorous diet, while maintaining the right calorie balance. This is because vegetable proteins have a lower bioavailability (absorption) than non-vegetable ones. Furthermore, it is necessary to vary and use different protein sources, so as to have a complete representation of all amino acids, especially the essential ones. The main vegan protein sources are legumes (for example soy), cereals (for example quinoa) and others (for example seitan);
- Considering Omega 3 fatty acids, vegans generally have a normal intake of alpha linolenic acid (ALA) but significantly low blood levels of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), of which ALA is a precursor. We therefore recommend increasing the ALA intake and possibly integrating DHA and EPA in the event of a deficiency. Sources rich in omega 3 are seeds (flax, chia, camelina, colza, and hemp), nuts and their oils.
As far as the contribution of micronutrients in the vegan diet is concerned, we observe that:
- Vegans consume similar quantities of iron as non-vegans but, being less bioavailable in vegan sources, it is easy to run into a deficiency. In fact, iron absorption levels are not only linked to the ingested source but also to the metabolic state of the individual at that time. Vegan sources of iron are soy, spirulina, lentils, tofu, quinoa, beans and chickpeas;
- Zinc blood levels may be lower in vegan subjects than in non-vegans but still included in the reference intervals. Zinc sources for vegan include pumpkin seeds, soy products, legumes, cereals and pecans. Food preparation techniques such as soaking and sprouting can increase their bioavailability;
- To maintain bone health, it is important to take the right amount of calcium, as well as of vitamin D. The calcium absorbed by the body is not only dependent on its presence in the food, but also on its bioavailability. Thus, we find foods (such as spinach and beets) very rich in calcium but in a poorly absorbable form due to the presence of oxalates, phytates and fibers. Other foods (such as cabbage and turnip greens) also represent an excellent source of calcium because they are easily absorbed, even if their content is low;
- The deficiency of vitamin B12 is the one that most involves vegans as the vegetable sources do not (today) provide this vitamin and the fermented products and algae are not sufficient. A lack in this vitamin causes symptoms such as unusual tiredness, tingling in the fingers and toes, poor digestion, mental fatigue and elevated homocysteine. Due to the low presence in vegan foods, integration through food supplements is required.
Scientific research has now shown that the vegan diet represents a safe approach at all stages of life, even in the most delicate ones such as pregnancy, breastfeeding, childhood and old age. Following a vegan diet can also be a valid ally in the prevention of chronic diseases such as obesity, diabetes and cardiovascular diseases. For a vegan approach to be safe, however, it must be balanced in all its nutrients, so that the body receives what it needs to live healthy.