October 2019 Issue
The Balance Between Plant and Animal Foods
By Toby Amidor, MS, RD, CDN, FAND
Today’s Dietitian
Vol. 21, No. 10, P. 32
Combining these two eating patterns can help clients meet daily nutrition requirements and promote better health.
Dietitians know plant-based diets have been a fast-growing trend in the past several years. With primarily plant-based eating patterns being associated with lower prevalence of CVDs, stroke, type 2 diabetes, certain cancers, as well as lower rates of heart disease risk factors such as hypertension and high cholesterol, more people are choosing to incorporate more plants into their diets than ever before.
However, plant-based eating has caused some confusion among consumers and even nutrition professionals, as the definition of “plant-based” isn’t clearly established. Both nutrition professionals and consumers have described plant-based eating as anything from a strict vegan or vegetarian diet to one that includes some animal foods. Other terms such as “plant forward” and “flexitarian” also are used to describe plant-based eating.
With all the media headlines and the non-evidence-based discussions about eating more plants, some consumers have been led to believe that animal-based foods, including meat, dairy, eggs, and fish, can’t be part of a well-balanced and healthful diet. They believe they must choose one type of eating pattern over the other, but that isn’t the case.
While vegan and vegetarian diets have been shown to provide several health benefits, the inclusion of animal-based foods also can provide nutrition and health benefits. This article will discuss the benefits of plant-based eating, review a variety of plant-based eating patterns, and describe how they can be combined with animal foods to meet nutritional requirements and promote overall health.
Benefits of Vegan and Vegetarian Diets
Research shows that eating a vegan diet is associated with “lower BMI, reduced risk of heart disease, type 2 diabetes, hypertension, and certain types of cancers,” says Sharon Palmer, MSFS, RDN, known as The Plant-Powered Dietitian and founder of the website and blog www.sharonpalmer.com. In addition, a vegan diet can “help lower blood pressure, cholesterol, and C-reactive protein [associated with inflammation]. It also has been linked with improved diabetes management and a better gut microbiome.”
However, despite these health benefits, only about 3.3% of American adults are vegetarian or vegan (ie, they never eat meat, poultry, or fish, or, in the case of vegans, never eat any animal products); and about 46% of vegetarians are vegan, according to a 2016 nationwide poll.1
Several of the health benefits linked with strict plant-based eating are supported in the literature. Many studies stemming from the EPIC-Oxford cohort found that, compared with omnivores who ate meat, fish, and poultry, vegetarians, including vegans, had a lower average BMI, lower systolic blood pressure, and a 32% lower risk of ischemic heart disease.2,3
A 2012 meta-analysis involving 124,706 participants examined cardiovascular mortality and overall cancer incidence among vegetarians and vegans. Researchers concluded that, compared with omnivores, vegetarians had a 29% lower ischemic heart disease mortality and 18% lower incidence of cancer.4
A 2009 study examined body weight and the association between the types of vegetarian diets and the prevalence of type 2 diabetes in men and women who participated in the Adventist Health Study-2. Researchers found that both vegan and lacto-ovo vegetarian diets were associated with approximately one-half the risk of developing type 2 diabetes compared with nonvegetarians. Pescatarian and semivegetarian diets (defined as consuming some dairy products and/or eggs and meat, similar to a flexitarian diet) were associated with one-third to one-quarter the risk of developing type 2 diabetes compared with nonvegetarians.5
Potential Nutritional Concerns of Vegan and Vegetarian Diets
According to a position paper on vegetarian diets from the Academy of Nutrition and Dietetics, “Appropriately planned vegetarian, including vegan, diets are healthful, nutritionally adequate, and may provide health benefits for the prevention and treatment of certain diseases.”1 To ensure optimal nutrient intake, those following vegetarian and vegan diets must plan carefully to consume the following nutrients through foods, or supplements if they’re unable to meet daily requirements through diet alone:
• Protein: Protein from a variety of plant foods eaten throughout the day can supply a sufficient amount of essential amino acids when calorie requirements are met. “If a vegan eats a balanced diet with protein-rich foods (eg, pulses, soyfoods, nuts, seeds, whole grains) at each meal, they can meet their needs,” Palmer says. “If they have higher protein needs for specific conditions [such as athletes], then they may need to work a little harder to increase their protein intake.”
• Omega-3 fatty acids: Alpha-linolenic acid from plant foods is converted to EPA and DHA, but the process is somewhat inefficient. Algae-based EPA and DHA supplements are available for those who can’t meet their requirements through alpha-linolenic acid and/or have increased needs.
• Iron: While iron deficiency is uncommon, vegetarians should focus on getting adequate iron, as nonheme iron isn’t absorbed as readily as heme iron. Iron supplements may be required, especially in vegetarians with increased needs.
• Zinc: Vegetarians tend to have lower zinc status (though within normal limits) compared with nonvegetarians. Zinc plant food sources include soy products, legumes, grains, seeds, and nuts. At-risk individuals, including older adults, pregnant and lactating women, and children, may need supplementation.
• Iodine: Plant-based diets can be low in iodine, especially if iodized salt or sea vegetables aren’t consumed. It’s recommended that vegan women of childbearing age take an iodine supplement containing 150 mcg/day.
• Calcium: Vegans’ calcium intake may fall short of recommendations. The low bioavailability of calcium found in high-oxalate and high-phytate vegetables makes them poor calcium sources, but other sources such as cruciferous vegetables and fortified soyfoods are good options. Dietitians should evaluate their clients’ diets and recommend good calcium sources—even calcium supplements if necessary.
• Vitamin D: Vitamin D status should be assessed to determine whether a supplement is necessary. Vitamin D is found in only a handful of foods, such as egg yolks, fatty fish, fortified milk, and beef liver, and some individuals may not get enough exposure to sunlight.
• Vitamin B12: This vitamin is found in animal foods. Some vegetarians and vegans turn to fermented foods, unfortified nutritional yeast, spirulina, and chlorella algae to get vitamin B12, but these foods aren’t sufficient. B12-fortified foods or supplements are needed, or individuals can combine plant and animal foods.
Combining Plant and Animal Foods
There are many healthful dietary patterns that include a combination of both animal and plant foods. These include the eating patterns, such as the Mediterranean and pescatarian diets, highlighted in the 2015–2020 Dietary Guidelines for Americans (DGA). Research shows that including animal foods in these plant-based diets offers nutritional and health advantages.
The DGA
The Healthy US-Style, Vegetarian, and Mediterranean-Style eating patterns are outlined in the DGA. The DGA, which steer away from focusing on individual nutrients, recommend three healthful eating patterns, all of which are plant based and inclusive of animal foods (ie, the vegetarian eating patterns include dairy and eggs); however, the DGA do state that a vegan diet, which excludes all animal foods by switching dairy products to fortified soymilk, is part of the approved vegetarian dietary pattern.
In most of these dietary patterns, both plant and animal foods contribute a unique set of nutrients. The Healthy US-Style eating pattern includes daily consumption of 2 1/2 cup equivalents of a variety of vegetables; 2 cup equivalents of fruits; 6 oz equivalents of grains (at least one-half of which should be whole); 3 cup equivalents of milk and dairy products; 5 1/2 oz equivalents of protein foods, including seafood, lean meats, poultry, eggs, legumes, nuts, seeds, and soy products; and 27 g of oil. Saturated fat, sodium, added sugars, trans fat, and overconsumed nutrients have maximum recommended limits.
A 2016 modeling study using National Health and Nutrition Examination Survey data found that a combination of plant and dairy foods could help close nutrient gaps commonly found in the United States. The study examined the nutritional impact of three dietary scenarios by doubling the intake of 1) plant-based foods; 2) protein-rich plant-based foods (eg, legumes, nuts, seeds, and soyfoods); and 3) dairy foods (eg, milk, yogurt, and cheese).
When plant-based foods were increased by 100%, individuals were more likely to meet their nutrient requirements for magnesium, iron, folate, and vitamins C and E. However, they were less likely to meet nutrient targets for calcium, protein, and vitamins A and D. When dairy foods were increased to two to four servings per day, more individuals reached their goals for calcium, protein, magnesium, and vitamins A and D. The study illustrated the balance of plant foods combined with animal foods to help close nutrient gaps that exist among Americans older than 2.6
The Mediterranean Diet
Compared with the Healthy US-Style eating pattern, the Healthy Mediterranean-Style eating pattern recommends more fruits and seafood and less dairy. Hundreds of studies have found benefits of the traditional Mediterranean dietary pattern, which is rich in whole grains, fruits, vegetables, beans, herbs, spices, nuts, and olive oil, with two servings per week of seafood, moderate portions of dairy foods and eggs, occasional poultry, and infrequent servings of red meat and sweets. It has been linked to longevity, improved brain function, reduced risk of chronic diseases, healthful weight, lower risk of depression, and improvement of rheumatoid arthritis.
In fact, Mediterranean diet scores have been validated and show that stronger compliance to the Mediterranean diet tenets is linked with better outcomes. However, some studies have looked at including additional servings of animal foods in the Mediterranean diet with intriguing impacts. The Healthy Mediterranean-Style eating pattern provides approximately 700 mg to 800 mg calcium per day, a limitation that falls 200 mg to 600 mg per day short of US recommendations depending on gender and age, according to the Dietary Reference Intakes.
A 2018 study looked at the consumption of three to four servings of dairy per day in the Mediterranean diet on markers for CVD risk. In this randomized controlled crossover design, 41 subjects who were at risk of CVD followed a low-fat diet or Mediterranean diet with three to four servings of dairy per day (designated the MedDairy group). Compared with the low-fat group, the MedDairy group had lower morning systolic and diastolic blood pressure, lower clinical systolic blood pressure, significantly higher HDL cholesterol, lower triglycerides, and a lower ratio of total to HDL cholesterol.
Researchers concluded that the Mediterranean diet benefits include reduced risk factors for atherosclerosis. In addition, the study found that adding at least one serving of dairy to the Mediterranean diet increased intake of calcium by 32%, vitamin D by 21%, and potassium by 8%.7 It should be noted that these three nutrients are underconsumed, as determined by the DGA.
A 2017 study looked at the association between lignans and yogurt consumption in the Mediterranean diet on cardiovascular risk parameters. This cross-sectional study used food frequency questionnaires in 7,169 Spanish PREDIMED participants. Researchers found that individuals eating the highest amount of yogurt or the highest amount of lignans (found in plant foods such as olive oil, wheat products, and tomato products) had fewer cardiovascular risk factors and lower blood glucose. However, those who consumed the highest amounts of yogurt and lignans together had even fewer cardiovascular risk factors than either food alone, once again displaying the balance between plant and animal foods.8
In addition, a 2018 study conducted at Purdue University demonstrated that following a Mediterranean-style eating pattern that incorporated lean, unprocessed meat, along with other animal protein sources, can support heart health. The study followed 41 overweight or obese adults for 16 weeks, and participants were divided into two groups. One group ate a typical US lean red meat diet (~18 oz/week), while the other group ate a diet that restricted lean red meat to about 7 oz/week).
The results showed that participants who consumed 18 oz of lean, unprocessed red meat per week, in addition to poultry and/or fish, as part of a healthful Mediterranean diet showed decreased total cholesterol, LDL cholesterol, and blood pressure.9 It’s important to keep in mind that the body of the evidence suggests that the traditional Mediterranean eating pattern, as defined previously, yields numerous benefits.
Flexitarian Diet
People who follow the flexitarian diet, dubbed semivegetarian, consume a plant-based diet that includes small portions of meat, chicken, and fish. In a recent survey, 14% of US consumers (more than 43 million people) regularly use plant-based alternatives such as tofu, almond milk, and veggie burgers. However, of these consumers, 86% don’t consider themselves vegan or vegetarian; a portion of these consider themselves flexitarian.10
Dawn Jackson Blatner, RDN, LDN, author of The Flexitarian Diet: The Mostly Vegetarian Way to Lose Weight, Be Healthier, Prevent Disease, and Add Years to Your Life, says, “Animal products can be part of a balanced diet,” adding that “flexitarianism is pro-plants, not antimeat.”
According to Blatner, “Research shows plant-based eating is extremely good for you, but you don’t have to give up meat completely to get health benefits. A flexitarian is someone who wants to be more vegetarian/plant-based but doesn’t want to be super strict and totally give up meat.”
A flexitarian diet, Blatner continues, is easy to follow because one doesn’t have to remove any food groups. In addition, “Flexitarians weigh 15% less; have a lower rate of heart disease, diabetes, and cancer; and live 3.6 years longer than their carnivorous counterparts.”
The following three strategies can help clients follow a more flexitarian eating pattern:
• Reportion the plate. Reduce meat portions while pumping up the produce. Aim to make 25% of the plate meat, poultry, or fish; 25% whole grains such as brown rice or whole grain pasta; and 50% veggies.
• Reinvent old favorites. Take their favorite recipes and swap out the meat for beans. For every 1 oz of meat, use 1/4 cup beans instead.
• Refresh your recipe repertoire. Try a new vegetarian recipe each week. Suggest clients ask friends for their favorites or look through vegetarian magazines and cookbooks for one that catches their eye.
The following is an example of one day on a flexitarian diet, courtesy of Blatner. The amount of animal foods depends on the individual.
• Breakfast: Avocado Toast (sprouted whole grain toast with avocado, spinach, and egg);
• Lunch: Kale Ranch Bowl (chicken or chickpeas, chopped kale and tomatoes, roasted sweet potato cubes, and ranch dressing);
• Dinner: Tacos (seasoned whitefish or lentils, corn tortillas, cabbage slaw, guacamole, and salsa); and
• Snack: Apple and pecans and/or cucumber plus hummus.
Recommendations for RDs
Overall, there’s no one-size-fits-all dietary pattern that will satisfy everyone. There are several healthful dietary patterns individuals can choose to follow that are in line with the DGA; adaptable to one’s beliefs, personal preferences, and culture; and that include plants only or plants plus animal foods.
As the trend in plant-based eating continues to grow, dietitians must stay abreast of the various types of healthful eating patterns and learn how to implement them. If RDs aren’t knowledgeable in a given area, Palmer recommends referring clients to RDs who specialize. The Vegetarian Nutrition Dietetic Practice Group is an excellent resource and place to start.
Whatever dietary pattern clients choose to follow, it’s important to look at their total diet pattern to ensure it’s balanced and includes underconsumed nutrients. This is especially true for vegan and vegetarian clients, since they may not be getting enough vitamin B12, vitamin D, calcium, iron, and omega-3s. However, dietitians can help their clients meet their diet preferences with appropriate education and guidance.
— Toby Amidor, MS, RD, CDN, FAND, is the founder of Toby Amidor Nutrition (http://tobyamidornutrition.com) and a Wall Street Journal best-selling author. Her cookbooks include Smart Meal Prep for Beginners, The Easy 5-Ingredient Healthy Cookbook, The Healthy Meal Prep Cookbook, The Greek Yogurt Kitchen, and the upcoming The Create-Your-Plate Diabetes Cookbook and The Best Rotisserie Chicken Cookbook Ever. She’s a nutrition expert for FoodNetwork.com and a contributor to U.S. News Eat + Run and Muscle&Fitness.com.
Toby Amidor, MS, RD, CDN, FAND, reports the following relevant disclosures: She serves as an essential dairy and plant-based advisory board member at Danone, spokespersons for California Strawberry Commission and Grapes from California, a beef expert bureau member and speakers bureau member for the National Cattleman’s Beef Association, and an ambassador for the National Dairy Council.
References
1. Melina V, Craig W, Levin S. Position of the Academy of Nutrition and Dietetics: vegetarian diets. J Acad Nutr Diet. 2016;116(12):1970-1980.
2. Spencer EA, Appleby PN, Davey GK, Key TJ. Diet and body mass index in 38000 EPIC-Oxford meat-eaters, fish-eaters, vegetarians and vegans. Int J Obes Relat Metab Disord. 2003;27(6):728-734.
3. Crowe FL, Appleby PN, Travis RC, Key TJ. Risk of hospitalization or death from ischemic heart disease among British vegetarians and nonvegetarians: results from the EPIC-Oxford cohort study. Am J Clin Nutr. 2013;97(3):597-603.
4. Huang T, Yang B, Zheng J, Li G, Wahlqvist ML, Li D. Cardiovascular disease mortality and cancer incidence in vegetarians: a meta-analysis and systematic review. Ann Nutr Metab. 2012;60(4):233-240.
5. Tonstad S, Butler T, Yan R, Fraser GE. Type of vegetarian diet, body weight, and prevalence of type 2 diabetes. Diabetes Care. 2009;32(5):791-796.
6. Cifelli CJ, Houchins JA, Demmer E, Fulgoni VL. Increasing plant based foods or dairy foods differentially affects nutrient intakes: dietary scenarios using NHANES 2007-2010. Nutrients. 2016;8(7):422.
7. Wade AT, Davis CR, Dyer KA, Hodgson JM, Woodman RJ, Murphy KJ. A Mediterranean diet supplemented with dairy foods improves markers of cardiovascular risk: results from the MedDairy randomized controlled trial. Am J Clin Nutr. 2018;108(6):1166-1182.
8. Creus-Cuadros A, Tresserra-Rimbau A, Quifer-Rada P, et al. Associations between both lignan and yogurt consumption and cardiovascular risk parameters in an elderly population: observations from a cross-sectional approach in the PREDIMED study. J Acad Nutr Diet. 2017;117(4):609-622.e1.
9. O’Connor LE, Paddon-Jones D, Wright AJ, Campbell WW. A Mediterranean-style eating pattern with lean, unprocessed red meat has cardiometabolic benefits for adults who are overweight or obese in a randomized, crossover, controlled feeding trial. Am J Clin Nutr. 2018;108(1):33-40.
10. Plant-based proteins are harvesting year-over-year growth in foodservice market and broader appeal. The NPD Group website. https://www.npd.com/wps/portal/npd/us/news/press-releases/2018/plant-based-proteins-are-harvesting-year-over-year-growth-in-foodservice-market-and-broader-appeal/. Published June 6, 2018.