Eat your fruit and veggies, but don’t neglect meat and dairy – that’s the latest conclusion of vitamin uptake research.
A recently published review by Riddet Institute food scientists Dr Sylvia Chungchunlam and Distinguished Professor Paul Moughan appeared in the academic journal Critical Reviews in Food Science and Nutrition, published online on July 31.
The Riddet Institute is a Centre of Research Excellence (CoRE), hosted by Massey University in Palmerston North. The institute focuses on advanced food research.
The review found mixed diets comprising animal- and plant-based foods continue to be the best option for optimal vitamin intake, sufficient to meet the vitamin needs of the human body.
Across a range of global research studies, the review looked at the quantity of a vitamin that is available to be used by the human body. This bioavailability was compared between food sources.
“This breakthrough in our knowledge of the comparative inherent bioavailability of vitamins amongst foods sources from animals and plants is of a strong nutritional significance,” Chungchunlam said.
“It is important from the standpoint of choosing appropriate vitamin-dense foods to meet the vitamin requirements of all.
“We are strongly encouraged to consume a plant-based diet at present, instead of animal-based foods,” Chungchunlam said.
“Most vitamins are naturally widely distributed in foods, but vitamin deficiencies are very common, despite what appears to be a good diet. Sometimes this may be due to inadequate absorption and utilisation of vitamins present in the diet.”
Vitamins are essential components of enzyme systems involved in normal growth and function. Bioavailability is the proportion of an ingested nutrient that is released during digestion and absorbed for use or storage in the body.
The review found that while bioavailability is highly variable among dietary sources, in general most vitamins in animal-derived foods, such as meat, milk, eggs and fish, are more bioavailable than the equivalent vitamins in plant-based foods, such as vegetables, fruits, legumes, cereal grains, nuts and seeds.
The review found that animal-sourced foods are the almost exclusive natural sources of dietary vitamin B-12 and preformed vitamin A retinol, and contain highly bioavailable biotin, folate, niacin, pantothenic acid and vitamin B-6. Vegetables and fruits are the main natural sources of vitamin C, provitamin A carotenoid β-carotene, and vitamin K. Riboflavin (vitamin B-2) and thiamine (vitamin B-1) were similarly bioavailable when foods are sourced from animals or plants.
The researchers noted that the bioavailability of naturally occurring choline, vitamin D, vitamin E, and vitamin K in food await further studies to evaluate the comparative bioavailability of these essential nutrients among animal- and plant-based foods.
“There have been many studies about the inherent bioavailability of vitamins naturally occurring in food, but the data were very scattered.”
Chungchunlam said before this study, there was no real comparison of the bioavailability of naturally occurring vitamins between animal-based and plant-based foods.
The review looked at the current state of knowledge for 13 essential vitamins, and the vital nutrient choline.
