Academy of Nutrition and Dietetics https://www.ncbi.nlm.nih.gov/pubmed/27886704/
"It is the position of the Academy of Nutrition and Dietetics that appropriately planned vegetarian, including vegan, diets are healthful, nutritionally adequate, and may provide health benefits for the prevention and treatment of certain diseases. These diets are appropriate for all stages of the life cycle, including pregnancy, lactation, infancy, childhood, adolescence, older adulthood, and for athletes."
Dietitians of Canada https://www.dietitians.ca/Downloads/Fac ... egans.aspx
"A healthy vegan diet can meet all your nutrient needs at any stage of life including when you are pregnant, breastfeeding or for older adults."
The British National Health Service http://www.nhs.uk/Livewell/Vegetarianhe ... diets.aspx
"With good planning and an understanding of what makes up a healthy, balanced vegan diet, you can get all the nutrients your body needs."
The British Nutrition Foundation https://www.nutrition.org.uk/bnf-public ... -nutrition
A well-planned, balanced vegetarian or vegan diet can be nutritionally adequate ...
The Dietitians Association of Australia https://daa.asn.au/smart-eating-for-you ... derations/
Vegan diets are a type of vegetarian diet, where only plant-based foods are eaten. With good planning, those following a vegan diet can cover all their nutrient bases, but there are some extra things to consider.*
The National Health and Medical Research Counci
l https://nhmrc.gov.au/about-us/publicati ... guidelines
Appropriately planned vegetarian diets, including total vegetarian or vegan diets, are healthy and nutritionally adequate. Well-planned vegetarian diets are appropriate for individuals during all stages of the lifecycle. Those following a strict vegetarian or vegan diet can meet nutrient requirements as long as energy needs are met and an appropriate variety of plant foods are eaten throughout the day*
Harvard Medical School http://www.health.harvard.edu/staying-h ... vegetarian
Traditionally, research into vegetarianism focused mainly on potential nutritional deficiencies, but in recent years, the pendulum has swung the other way, and studies are confirming the health benefits of meat-free eating. Nowadays, plant-based eating is recognized as not only nutritionally sufficient but also as a way to reduce the risk for many chronic illnesses.
But, the tabloid magazines and some guy with a blog said it's unhealthy. Therefore, the largest organizations of nutrition professionals in the world must not know what they are talking about. Sounds reasonable.