Vegan basics and allergies
There are many myths going around about the plant based diet - many think that vegans may lack B12, iron, are weak and skinny and will develop a series of malnutrition signs if they stop eating meat and dairy products. Fortunately, these myths are only that - myths. In fact, vegan diets can meet nutrient requirements and can be an appropriate choice for all life stages, including pregnancy, lactation, infancy, and childhood, provided that they are well-planned. 
Milk and strong bones
Since we were little we have been told to drink dairy milk as it contains calcium and therefore is good for our bones. But is it?
This is actually an old myth that dairy farmers started and sold to the public very well. It was even more implemented in peoples minds with the Got milk advertisement back in 1993.
However, research shows that dairy products have little or no benefit for bones. A 2005 review published in Pediatrics showed that drinking milk does not improve bone strength in children. In a more recent study, researchers tracked the diets, exercise, and stress fracture rates of adolescent girls and concluded that dairy products and calcium do not prevent stress fractures.
Researchers in Sweden published findings in the British Medical Journal showing that women who drink milk have a higher incidence of bone fractures and an increased risk of mortality from heart disease and cancer.According to the study, women who consume three or more glasses of milk per day have a 60 percent increased risk of developing a hip fracture and a 93 percent increased risk of death. And each glass of milk increases mortality risk by 15 percent.
A new study in the International Journal of Cancer highlights the link between dairy consumption and prostate cancer.
Vitamin D in eggs and dairy
According to four different studies, if you were to take white button mushrooms and place them in the midday sun for 15–20 minutes, they would form enough vitamin D to provide more than 10μg per 100g of fresh mushroom, which would give you the recommended daily dose of vitamin D.
Exposed to enough sunlight, our bodies can make Vitamin D3. When mushrooms receive adequate sunlight they can make Vitamins D2 and D4; while shiitake mushrooms can make D2, D3, and D4. In fact, all commonly consumed mushrooms seem to have pro-vitamin D4, and the ability to convert this into D4 given the right UV conditions.
Omegas are present in fish and not eating them will make you deficient
Omega-3 (ALA) and omega-6 (LA) fats affect our immune system, brain, nerves and eyes. Fish get omegas through eating microalgae.
Our bodies can turn ALA fats into others, including EPA and DHA. To help our bodies convert ALA into EPA and DHA, we can:
Use vegetable oil (rapeseed) instead of sunflower, corn or sesame oil
Make sure that we include ALA sources into our everyday food, such as chia seeds, ground linseed, hemp seeds and walnuts
Supplement omega-3 made from microalgae (especially important during pregnancy and breastfeeding)
Source: The vegan society
Vegans don't get protein as protein comes from meat
When we hear about protein, it is largely associated with muscle growth and eating animal bodies or chicken eggs. However, protein is made up of amino acids. Human bodies need 20 amino acids, 11 of which we make on our own and 9 that we need to consume through our diet.
It may come as a surprise, but the largest study that compared the nutrient consumption of meat-eaters with plant-eaters showed that the average plant-eater gets 70% more protein than they actually need.
The game changers movie found, that while the animal protein package sabotages our ability to perform and feel our best, the plant protein package does the opposite. Why? Because plant protein comes together with fiber, antioxidants and phytochemicals such as vitamin C and carotenoids. The plant protein package has also shown to optimize the gut microbiome, which means that we can lower the inflammation in our bodies by 29% in just three weeks.
Source: The game changers documentary
Vegans are weak and malnourished
This one unfortunately has not left the mouths of meat eaters, even though a plant based diet is gaining more and more popularity with global warming. What do people need in order to thrive? The right food, which gives them energy that they can use to function every day. To do that, people do not need to eat a lot of protein, they need carbohydrates, which are only available in plants. Even further, animal based foods are making us sick. More than 60% of all global deaths are due to chronic diseases and conditions such as cardiovascular disease, type 2 diabetes, obesity, and certain cancers, with poor diet considered a major contributory factor in all of them. (Source)
Soy contains estrogen and is not good for men or boys
Nutrients in food