While some have suggested a plant-centered eating plan may be better for health and more environmentally sustainable than animal foods, more research is needed, and it is unclear what the nutritional impact will be -- especially among adolescent girls. National Dairy Council’s Nutrition Research team conducted a research study to find out.
Adolescence is a unique time period. Youth start to exercise their own independent behaviors and develop habits that can carry forward throughout adulthood. Additionally, adolescence marks a phase of rapid physical growth increasing the needs of several nutrients, including vitamin D, iron, zinc, folate, energy (i.e., calories) and protein. Adolescent girls can be at greater risk for not meeting the recommended amounts of nutrient than their male counterparts, thus it is critical that the foods they eat are nutrient rich foods including milk, cheese and yogurt. Milk is a good or excellent source of calcium, protein, phosphorus and vitamins A, D, B12, riboflavin, pantothenic acid and niacin.
Using data from What We Eat in America 2007-2010, the nutrition component of the National Health and Nutrition Examination Survey (NHANES), we modeled three different scenarios in adolescent girls:
- What would happen if they followed a blanket recommendation of doubling their consumption of plant-based foods in place of animal protein.
- Since we anticipated overall protein consumption would decrease in scenario 1, we also showed what would happen if adolescent girls doubled their consumption of only protein-rich plant based foods in place of animal protein.
- Additionally, dietary guidelines in the United States and elsewhere recommend adolescents eat three to four servings of dairy foods per day for optimal nutrition; therefore, we also showed the impact of meeting these dietary recommendations by doubling the dairy foods currently eaten to meet those guidelines, without any further adjustments to the diet.
The data showed that doubling plant-based foods resulted in:
- Increased consumption of dietary fiber, added sugar, vitamin E, iron and folate.
- Decreased consumption of total fat, saturated fat, zinc, vitamin D, calcium and protein intake.
When protein-rich plant foods were doubled there was no real nutritional impact because the usual consumption of these foods was already very low.
Doubling dairy foods increased consumption of vitamin D, magnesium, zinc, calcium, potassium, energy (i.e., calories), saturated fat and protein.
The results of this study show that if adolescent girls follow the general non-specific recommendations of increasing plant-based foods in place of animal foods it can lead to some nutritional benefits, but also unintended consequences, including lowered consumption of protein, and three of the 2015 Dietary Guidelines nutrients of concern—calcium, potassium and vitamin D. For adolescent girls, meeting the dietary recommendation of three servings of dairy per day improved their consumption of nutrients of concern (vitamin D, calcium, potassium) and simultaneously increased their consumption of nutrients that are essential for proper growth and bone health; however, calories should be adjusted to maintain weight.
Overall, more research is needed to determine what eating pattern is both nutritious and good for the environment, but these results reinforce the importance of a well-balanced eating plan composed of nutrient-rich foods for meeting nutrient adequacy, caloric needs and health.