This new article from the Faculty of Health and Sport Sciences at the University of Zaragoza, Spain, is quite a good summary on vegan nutrition. I could track down the Spanish original version (if there is one) - maybe you can.
"A vegan diet can meet nutritional requirements if it is well planned."
"[U]na dieta vegetariana puede satisfacer las necesidades nutricionales si está bien planificada."
"All vegans need to identify a source of vitamin B-12 in their diet
by means of fortified foods as vegetable beverages, breakfast cereals,
meat analogs or yeast. Vitamin D is not a problem if vegans
have adequate sun exposure, although it can also be obtained
from fortified foods (5). Although dairy foods are the most common
source of calcium, vegans find it in fortified foods such as fruit
juices, vegetable beverages and breakfast cereals (8,9). A vegan
diet can easily meet human dietary protein requirements with an
adequate energy intake and through consumption of a variety of
plant sources such as whole grains, legumes, grains, nuts and
seeds; nevertheless, they can also use soy products and meat
analogs as another source of protein (5,10). Requirements of
omega-3 fatty acid, a nutrient found in fish, can be located in
vegetal sources such as ground flaxseed or flaxseed oil, walnuts
and canola oil"
by means of fortified foods as vegetable beverages, breakfast cereals,
meat analogs or yeast. Vitamin D is not a problem if vegans
have adequate sun exposure, although it can also be obtained
from fortified foods (5). Although dairy foods are the most common
source of calcium, vegans find it in fortified foods such as fruit
juices, vegetable beverages and breakfast cereals (8,9). A vegan
diet can easily meet human dietary protein requirements with an
adequate energy intake and through consumption of a variety of
plant sources such as whole grains, legumes, grains, nuts and
seeds; nevertheless, they can also use soy products and meat
analogs as another source of protein (5,10). Requirements of
omega-3 fatty acid, a nutrient found in fish, can be located in
vegetal sources such as ground flaxseed or flaxseed oil, walnuts
and canola oil"
Reference:
Menal-Puey S, Morán Del Ruste M, Marques-Lopes I: Nutritional composition of common vegetarian food portions. Nutr Hosp 2016 Mar 25;33(2):121. doi: 10.20960/nh.121.