Whey Protein and Vegetarian Sources: A Comprehensive Guide

The question of protein adequacy in vegetarian diets has been a long-standing topic of discussion. While animal products are often considered primary protein sources, vegetarians can obtain sufficient protein from a variety of plant-based foods. This article examines protein intake from vegetarian diets, protein sources for vegetarians, and the role of whey protein.

Protein Intake in Vegetarian Diets

Protein Intake Gradients

Most studies indicate a gradient of protein intake, with meat-eaters consuming the most and vegans the least. Studies like EPIC-Oxford and Nutrinet-Santé have reported this gradient among adults in western countries. For example, the EPIC-Oxford study showed the following gradient: meat-eaters > fish-eaters > lacto-ovo-vegetarians > vegans. The French Nutrinet-Santé cohort reported a similar gradient, with protein intake at approximately 17.5% of energy for meat-eaters and 13% for vegans.

Exceptions to the Gradient

The Adventist Health Study 2 (AHS-2) presents a notable exception, where protein intake among lacto-ovo-vegetarians and vegans was strikingly similar to that of fish-eaters, semi-vegetarians, and non-vegetarians. This could be attributed to non-vegetarians in AHS-2 having a predominantly plant-based diet, with about 60% of their protein coming from plants, contrasting sharply with standard Western diets.

Factors Influencing Protein Intake

The gradient in protein intake across the vegetarian spectrum is likely due to high animal protein intake in standard Western diets. Individuals transitioning to vegetarian diets from these high-animal protein backgrounds may opt for lower-protein plant foods, compared to those accustomed to more traditional plant-based diets.

Adequacy of Protein Intake from Vegetarian Diets

General Protein Intakes

In Western countries, protein intake has significantly increased over the past century, aligning with increased consumption of animal products. In most industrialized countries, the protein intake of the general adult population reaches approximately 100 g/day, i.e., 1.3-1.4 g/kg/day, which is about twice the Estimated Average Requirement (EAR) of 0.66 g/kg/day.

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Protein Adequacy in Lacto-Ovo-Vegetarians

Lacto-ovo-vegetarians, with a protein intake of about 14% of energy intake in studies like EPIC-Oxford and Nutrinet, typically consume around 1.04 g/kg body weight, i.e., 70 g/day. This is higher than the Recommended Dietary Allowance (RDA) of 0.8 g/kg body weight, suggesting few people would have intakes below their requirements.

Protein Adequacy in Vegans

Studies on vegans, including EPIC-Oxford, Nutrinet, and AHS-2, report an average protein intake of approximately 13-14% energy, ranging from 62 g/day to 82 g/day. These intakes are generally above the 10% threshold considered the lower bound of acceptable intake. However, some studies, like the French Nutrinet-Santé, indicate that about 27% of vegans may have values lower than 10% energy. The EPIC-Oxford sample reported that 16.5% of men and 8.1% of women vegans had protein intakes lower than their requirement, based on the EAR cut-off method.

The Adventist Health Study Findings

The AHS study reported that even the lowest intakes in their vegan population were generally higher than the reference value, with protein intake at the 5th percentile being 10.1% of energy. This suggests that protein intake was likely adequate for most vegans in this survey.

Caveats in Estimating Protein Adequacy

Estimating the prevalence of protein inadequacy has limitations due to uncertainties and biases in dietary surveys. Standard methods offer good accuracy in classifying subjects into categories of relatively higher vs. lower intakes, but absolute quantitative precision remains low.

High-Protein Vegetarian Food Sources

If you want to try a vegetarian diet, you can get protein from plant-based foods like legumes and beans, nuts and seeds, whole grains, vegetables, dairy, and eggs.

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Legumes and Beans

Beans and legumes are excellent sources of protein for vegetarians, suitable as meat replacements in various dishes. They include lentils, black beans, fava beans, chickpeas, garbanzo beans, kidney beans, lima beans, and soybeans.

Nuts and Seeds

Nuts and seeds are also good sources of protein, consumed as snacks or sprinkled on meals. Nut- and seed-based spreads are protein-rich. Popular options include peanuts, almonds, cashews, hazelnuts, pecans, pistachios, walnuts, pumpkin seeds, sesame seeds, and sunflower seeds.

Whole Grains

Whole grains, eaten in their natural form, provide protein, vitamins, and minerals. Examples include oats, barley, quinoa, farro, millet, sorghum, brown rice, and whole wheat.

Vegetables

Leafy greens and vegetables contain fiber, vitamins, and minerals, with some being relatively high in protein. Brussels sprouts, peas, corn, asparagus, broccoli, and lima beans are good choices.

Dairy

Dairy contains whey and casein proteins. Whey digests quickly, while casein digests slowly. Dairy products like Icelandic skyr, Greek yogurt, cottage cheese, mozzarella cheese, cheddar cheese, whole milk, and low-fat yogurt are good protein sources.

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Eggs

One large egg contains 6-8 grams of protein and all nine essential amino acids.

High-Protein Foods for Vegan Diets

Vegans exclude all animal products, necessitating alternative protein sources.

Tempeh and Tofu

Tempeh and tofu, made from soy, are rich in protein. One cup of tempeh has 34 grams of protein, and tofu has 44 grams.

Seitan

Seitan is made from gluten from wheat flour dough and contains almost 25 grams of protein per serving.

Beans

Beans are versatile replacements for animal protein in meals. Chickpeas, kidney beans, pinto beans, and navy beans contain 15-18 grams of protein per cup. Lentils and split peas contain 18 grams and 16 grams, respectively.

Edamame

Edamame (young soybeans) can be boiled, steamed, or dry roasted and contain up to 18 grams of protein per cup.

Whole Grains

Quinoa, farro, and black rice can be used as meal bases or side dishes. One cup of quinoa has 8 grams of protein, while one cup of black rice has 16 grams.

Soy or Oat Milk

One cup of oat milk has 3 grams of protein, while one cup of soy milk has almost 8 grams.

The Role of Protein

Protein is crucial for building muscles and bones, repairing damage, transporting oxygen, digesting food, and regulating hormones. It comprises 20 amino acids. Animal protein is complete, containing all essential amino acids. Most plant proteins are incomplete, requiring a variety of plant foods to obtain all necessary amino acids.

Benefits of Plant-Based Diets

Plant-based diets lower the risk of health problems like obesity, heart disease, stroke, and diabetes. Animal protein is easier to digest and has more omega-3 fatty acids, vitamin B12, and vitamin D. However, diets with animal protein tend to have higher levels of fat, calories, and sodium.

Protein Powders

Protein powders are dietary supplements providing a concentrated protein source. They are used to increase muscle mass, improve athletic performance, and supplement diets.

Types of Protein Powders

• Whey Protein: Derived from milk, it is fast-digesting and quickly absorbed, improving muscle protein synthesis.
• Casein Protein: Digested slowly, it helps build muscle, reduce appetite, and increase fullness.
• Plant-Based Protein: Derived from plants like chia, pumpkin, hemp, flax seeds, quinoa, and brown rice, it often contains micronutrients like antioxidants, vitamins, fiber, and minerals.
• Soy Protein: Acts as a substitute for meat proteins and supports healthy weight management.
• Egg White Protein: Promotes healthy muscle maintenance with a combination of essential amino acids.

How to Incorporate Protein Powder

Protein powder can be added to shakes, oatmeal, pancakes, waffles, and Greek yogurt. It facilitates recovery after workouts and provides a hearty dose of protein in the morning.

Protein for Runners

Runners require protein for muscle repair and growth. Endurance athletes benefit from consuming up to 0.82 grams of protein per pound of bodyweight, especially on training days. Studies show that as long as extra protein needs are met, even from plant sources, there is no reduction in muscle endurance, strength, or size.

Longevity Benefits of Plant Proteins

A study in the American Journal of Clinical Nutrition in 2024 found that higher plant protein intakes are linked to healthier aging, defined as being free of chronic diseases and having no impairment in mental and physical functioning. Replacing 3 percent of calories from animal protein sources with plant protein sources increased the odds of healthy aging by 38 percent.

Plant-Based Diets and Athletic Performance

A systematic review and meta-analysis published in 2024 found that plant-based diets can help athletes perform better during aerobic activities and do not have a detrimental effect on strength performance.

Top Plant-Based Proteins for Vegetarians

1. Soy Milk: Contains 3.6 grams of protein per ½ cup. Soy milk is one of the few plant-based milks with a protein content on par with cow’s milk.
2. Hemp Seeds: Contains 9.5 grams of protein per 3 tablespoons. Hemp seeds deliver a bigger dose of protein than most nuts and seeds.
3. Tempeh: Contains 34 grams of protein per 1 cup. It is denser in muscle-building protein than tofu, tempeh is also a richer source of dietary fiber, which can support a healthy microbiome.
4. Legume Pasta: Contains 13 grams of protein per 1 cup of cooked chickpea pasta. Noodles made from legumes offer up about twice as much protein as regular wheat-based noodles.
5. Edamame: Contains 9 grams of protein per ½ cup, prepared from frozen. Soybeans have significant amounts of high-quality protein, more than almost any other legume, and 8 grams of dietary fiber.
6. Fungi-Derived Mycoprotein: It is a complete protein that provides all essential amino acids, which isn’t typical of plant-based protein sources.
7. Freekeh: Contains 5 grams in ¼ cup dry serving. Typically, it has higher protein content than other grains, including quinoa.
8. Meatless Burgers: Contains 19 grams per burger. Beef-free grounds are a viable option to add more protein to your diet.
9. Plant Protein Powder: Contains 20 grams per two-scoop serving. Plant protein powders can help with building muscle just as much as animal-based powders, including whey.
10. Peanut Butter: Contains 7.5 grams in 2 tablespoons. Peanut butter provides more protein than spreads made from tree nuts.

Whey Protein and Vegetarianism

Whey protein is a popular supplement for building or retaining muscle mass, increasing power and strength, and aiding in weight loss.

Is Whey Protein Vegetarian?

Whey protein is vegetarian because vegetarians typically avoid animal meat but consume products made by or from animals, such as dairy. Whey protein is derived from cow’s milk. Vegans, however, typically avoid whey protein as they exclude all animal products and products produced by animals.

What is Whey Protein?

Whey protein is one of the major components of milk, derived from the liquid that separates from the curds during cheese production. It accounts for about 20% of the protein in cow’s milk and is low in lactose, making it easily digestible.

Forms of Whey Protein

• Whey Concentrate: Refined to remove water, fat, and lactose.
• Whey Isolate: More concentrated.
• Whey Hydrolysate: Broken down into smaller amino acid chains for quicker absorption and digestion.

Types of Vegetarianism

• Lacto-vegetarian: Includes dairy products but not meat, pork, or poultry.
• Ovo-vegetarian: Includes eggs but not meat, pork, or poultry.
• Pescetarian: Includes fish but not meat, pork, or poultry.
• Lacto-ovo-vegetarians: Eat dairy products and eggs.
• Ovo-pescatarians: Eat eggs and fish, but not dairy products.

Vegetarian Protein Sources

• Dairy: Rich in high-quality protein, available in varying degrees of fat and added sugars.
• Eggs: Higher in fat and cholesterol than low-fat dairy options.
• Fish: A range of options from low fat to omega-3 rich protein sources like salmon.
• Plant-based Sources: Beans, peas, soy, lentils, and whole grains like quinoa or brown rice.

Plant-Based Protein Powders

Made from soy, rice, hemp, or pea proteins, plant-based protein powders may not contain all essential amino acids. Whey protein is more widely available and typically lower in cost.

Plant-Based vs. Whey Protein Powders

How They’re Made

Whey protein powders are isolated from whey, a byproduct of cheese making. Plant-based protein powders are derived from plants like brown rice, pea, soy, and hemp.

Protein Content

Whey and plant-based protein powders contain similar amounts of protein, averaging 20-30 grams per serving. Whey protein is a complete protein with all nine essential amino acids and branched-chain amino acids (BCAAs). Only soy protein powder is considered complete among plant-based options.

Digestibility and Food Sensitivities

Whey protein contains lactose, a common food sensitivity. Plant-based protein powders can contain soy and gluten. Some, especially those with pea protein, may cause bloating and cramping.

Cost

Prices for both types depend on the brand, with specialized qualities often costing more.

Muscle Building

Whey protein isolate is considered the gold standard for muscle growth. Plant-based protein powders can also be complete proteins and contain high amounts of leucine, provided that they contain two or more plant proteins or are fortified with BCAAs.

Weight Loss

Both whey and plant-based protein powders can help promote fullness and preserve lean muscle mass.

Best Practices for Protein Powder Use

• Stick with protein-only supplements: Opt for a protein powder that contains just protein.
• Look for 100-150 calories or fewer per serving: This may indicate a protein powder with minimal added ingredients.
• Be mindful of smoothies: Avoid too many additions that can lead to extra calories.
• Add it to other foods: Try adding protein powder to whole foods like pancakes or oatmeal.
• Don’t use it as a meal replacement: They don’t contain enough nutrients or calories to be considered meals.
• Incorporate strength training: This can help preserve muscle mass and promote muscle building.
• Consult a dietitian: If you need help figuring out how to best incorporate protein powder to meet your individualized weight loss goals.

Choosing the Right Protein Powder

Choosing a protein powder is individual. Consider dietary needs, preferences, and any sensitivities. Look for versions with minimal ingredients and 20-30 grams of protein per serving.

Whey and Rennet

Rennet, an enzyme used in cheese making, can be derived from animal or vegetable sources. Whey, being a byproduct of cheese making, may or may not be vegetarian, depending on the source of rennet used. Sweet whey, derived from rennet-coagulated cheese, may or may not be vegetarian.

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