Supplements, protein, and nutrients, oh my! There’s tons of nutrition advice about vegan diets out there, but who can we really believe? Although anyone can call themselves a nutritionist or nutrition expert, registered dieticians and registered dietician nutritionists have years of specialized education, supervised training and professional credentials.

Vegan registered dietician Karla Moreno-Bryce, the founder of, generously donated her time to answer questions for this blog post. Karla Moreno-Bryce began her vegan journey in 2008, and she created Nutritious Vida as a platform that brings together her passion for cooking and nutrition to help educate and inspire others in adopting a healthful vegan lifestyle. Karla has tons of educational and professional credentials as a nutrition expert.*

Here are Karla Moreno-Boyce’s answers to the top 10 questions vegans teens asked. Thanks so much to Karla Moreno-Boyce for donating her time! 

Is consuming soy foods safe, and does it affect hormones in teens?

Soy continues to be a controversial legume. Soy has brought fear to many consumers regarding its consumption, but there are so many great health benefits to the variety of soy foods we now have available. In fact, soy is one of the most researched legumes out there, and there is sufficient evidence to show that soy foods are safe at any age of the life cycle, and that they do not affect hormones in teens or any other age group.

There are a couple of myths about soy that continue to circulate conversations, such as: (a) soy causes feminization in men or teen boys, (b) soy causes breast cancer, and (c) all soy products are made from GMOs. The reason behind the first two myths stems from the fact that soy foods have isoflavones, which have a similar structure to that of the estrogen hormone. However, isoflavones and estrogen are not the same, as their function is different when they bind to cell receptors. Soy doesn’t necessarily affect hormones in men or teen boys, because this has not been shown to be true in human studies. This effect has only been studied in rats and mice, and they metabolize soy differently than humans do. Additionally, soy has been shown to reduce the risk of developing breast cancer – especially when consumed at a young age. Lastly, not all soybeans are made with GMO practices. The majority of GMO soybeans produced are for animal feed or other by-products. Soy products made for food consumption, such as tofu or meat analogs, are generally non-GMO foods. Look for “organic” or the “non-GMO project” icon on the labels to ensure they exclude any method of GMOs.

Some claim coconut oil is healthier than other oils. Is this true and should we consume coconut oil at all?

Coconut oil is about 92% saturated fat and some research studies raise the confusion of whether plant saturated fats plays a positive role in health. There are many claims out there about the use of coconut oil, such that it promotes weight loss, helps reduce the risk of heart disease and that it’s a “healthier” oil than other plant oils; however, the science isn’t really there to back these claims. Much of the research that has shown positive health benefits to certain diseases are based on small human studies and thus more research is needed. But that doesn’t mean that coconut oil should be completely eliminated from your diet. It can be part of a balanced diet if adding coconut oil in moderation to flavor dishes or used for baking. Include more plant foods that provide mono- and poly-unsaturated fats into your diet, such as avocado, walnuts, olives, flaxseeds, and soybeans.

What are the three most essential supplements to take on a vegan diet?

No matter how balanced a vegan diet may be, all vegans, regardless of age, need supplementation. It’s possible to meet many of the vitamins and minerals we need for our body to thrive solely from plant foods, but there are a few exceptions when following a vegan lifestyle. One supplement that all vegans need is Vitamin B12. It’s important to consume a daily Vitamin B12 supplement even if the diet includes fortified foods with Vitamin B12. Choose a supplement that offers the cyanocobalamin form of Vitamin B12 and supplies 500 to 1,000 mcg.

The second supplement that most vegans need is Vitamin D. Depending on where you live, many of us can obtain adequate amount of Vitamin D by spending 15 to 20 minutes outdoors on a sunny day. This is because our skin can convert the previtamin D3 into Vitamin D3 when exposed to ultraviolet light from sunlight. Several sources of food provide Vitamin D, but the majority come from animal products. Foods such as fortified plant milks, fortified orange juice, and ready-to-eat cereals are a few plant sources that provide Vitamin D. Consider taking a supplement that provides 600 to1,000 IU (15 to 25 mcg) per day.

Lastly, calcium is a supplement that most vegans need. Without consuming fortified plant foods that supply calcium, many vegan teens, particularly adolescent girls, still fall short in getting enough of this important mineral. This could potentially increase the risk of osteoporosis if low intakes of calcium are consumed over a long period of time. Although many multi-vitamin supplements contain calcium, the majority of them contain very little amounts. Consider taking a daily supplement to obtain the recommended daily value of 1,300 mg per day for teens.

Can you obtain adequate calcium from plant foods or fortified foods?

Calcium is the most abundant mineral in the body, as its primariy role is to support bone and teeth structure. Teens (ages 13 to 18) need about 1,300 mg of calcium per day and can meet their needs with proper meal planning that contains good sources of calcium and fortified foods. In fact, consuming adequate amounts of a variety of protein sources throughout the day can help calcium absorbtion. Vegetables like kale, broccoli, and bok choy are good sources of calcium to add to your diet. In addition, calcium-fortified tofu and orange juice provide about 300mg of calcium in 1 cup, which is about 23% of your daily need for calcium. Despite consuming good source of plant foods that provide calcium, many still fall short on this important mineral during time of growth. If you want to ensure you are meeting your needs, consider taking a daily supplement.

What is the recommended amount for omega-3s for teens? Is a supplement needed or can you obtain adequate amounts from plant foods?

Omega-3’s play an important role in maintaining healthy cells for the brain and eyes. There are three types of omega-3’s: alphalinoleic acid (ALA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). ALA is an essential nutrient found in several plant sources and can be converted to EPA + DHA; however, the amount converted tends to be low. EPA and DHA are only found in microalgea and sea vegetables; however, sea vegetables are not really a reliable plant source for omega-3 fatty acids. Consume plant sources that provide ALA, such as walnuts, chia seeds, flax seeds, hemp seeds, canola oil, and soybean products. In addition to these foods, it is also recommended to take an omega-3 supplement every 2-3 days. There is currently not a recommended amount for omega-3, except for the ALA form. For teens, it is recommended to consume 1.0 to 1.1 grams for teen girls and 1.2 to 1.6 grams per day for teen boys. Just 1 tablespoon of ground flaxseed provides about 1.6 grams, which can easily be sprinkled in cold cereal or added to smoothies. You can meet your daily needs for ALA through a variety of plant sources, but it wouldn’t hurt to also take a supplement to ensure you are obtaining all forms of omega-3 fatty acids.

Can you obtain and absorb adequate iron from plant sources? How much iron should teens be getting each day?

Iron is an essential mineral that the body needs for proper growth and developtment. Its primary role is to make hemoglobin, which is a protein that helps carry oxygen throughout the body. There are two types of iron: heme iron (primarily found only in animal products) and non-heme iron (only found in plants). You can obtain adequate amounts of iron from plant sources, and it is best to include foods rich in Vitamin C in meals that provide iron to increase its absorption. Some plant sources that provide iron are: beans, lentils, green leafy vegetables, nuts & nut butters, enriched pastas, quinoa, tofu, and prunes. The recommended amount for teen boys (ages 14 to 18) is 11 milligrams per day and 15 milligrams for teen girls. Teenage girls need a little more iron due to menstration. About 1/2 cup of cooked lentils provide 3.3 milligrams. Consume a variety of plant foods that provide iron, coupled with a source of Vitamin C, to meet your daily needs.

What should every vegan or vegetarian make sure to eat consistently to ensure proper nutrition?

Vegan teens have the same nutrition requirements as other teens, the difference being that these nutrients are obtained in an alternate way. To ensure proper nutrition during this period of growth, a teenager’s diet should include a variety of foods, like legumes, nuts, seeds, fruits, vegetables, and whole grains, and make sure that enough calories are eaten throughout the day for proper growth. The key to a healthy vegan diet is not necessarily eating the same thing every day, but rather eating a variety of plant sources. This will not only ensure that you’re getting vitamins and minerals from different foods, but you will also be able to enjoy the abundance of plant foods that are available to eat.

How much protein should teens be getting, and is a protein powder necessary?

Most vegan teens rarely have any difficulty obtaining adequate amounts of protein. Those who do not obtain enough protein normally are not consuming the amount of calories required for growth. Good sources of plant protein foods are beans, lentils, tofu, peanut butter, whole grain bread, quinoa, and seeds, such as hemp seeds. The theory that you must combine protein to make a “complete protein” is untrue. In fact, your body naturally does this on its own simply by consuming a variety of protein sources throughout the day, since all plant foods provide all the essential amino acids that the body needs to make proteins.

Teens need about 0.85 gm/kg/day and teen athletes need about 1.3 to 1.8 g/kg/day. To calculate, simply take your body weight in kilograms and multiply it by the reference number (i.e. 45 kg x 0.85 g/kg = 38 grams per day). This is simply a general reference for age, and note that each individual may need different amounts of protein depending on the situation. Nonetheless, if you consume adequate amounts of protein sources in each meal and snack, then you don’t have to worry about calculating how much you need, or even have to supplement with protein powders. To give you a reference, one slice of whole grain toast with a serving of peanut butter (2 tablespoons) provides about 13 grams of protein, and 1/2 cup of firm tofu provides about 10 grams.

How much Vitamin B12 should teens be getting? What foods are the best source to obtain this nutrient?

Vitamin B12 is needed for proper red blood cell formation and helps keep nerve cells healthy. It is naturally found in animal products but not present in plant foods unless fortified. The recommended amount for children 9 to 13 years of age is 1.8 micrograms (mcg) and 2.4 mcg per day for ages 14 and older. Vitamin B12 can be found in several plant foods such as fortified plant “milks,” nutritional yeast, meat analogs, and ready-to-eat cereals. It is best practice to read the Nutrition Facts Label to make sure that Vitamin B12 has been added to these plant-based products. It is important to ensure adequate amount of Vitamin B12 is consumed throughout the day for good health.

Even if you consume adequate amounts of Vitamin B12 from a variety of fortified plant foods, it is recommended to still take a daily supplement that provides Vitamin B12 to prevent any deficiency (i.e. nerve cell damage or megaloblastic anemia). Take a daily supplement of Vitamin B12 of 5 to 10mcg – preferably the cobalamin form rather than methylcobalamin. This isn’t because one is better than the other; it’s simply due to the fact that cobalamin has been well-studied and recommended by vegan experts.

My family is not vegan, and I am sometimes limited in what I can take to school for lunch. What are some simple lunch ideas that I can pack to take to school?

There are many school lunch ideas that you can prepare ahead of time without having to spend a lot of time in meal planning. Here are some ideas that you can do at home with simple and common ingredients:

• Veggie & Hummus Sandwich (whole grain bread, hummus as spread, spinach, tomatoes or other veggies of choice)

• Mediterranean Orzo Salad (cooked orzo, finely chopped kale, cubed cucumber, olives, chickpeas with olive oil, lemon, and dry basil)

• Spring Mix Salad with Pepitas (pumpkin seeds) (spring mix lettuce, northwestern beans, cherry tomatoes, shredded carrots, cranberries, pepitas with your choice of dressing)

• Falafel Pita (pita bread, falafel, shredded lettuce, cucumbers, olives, vegan mayo)

• Spicy Tempeh Veggie Wrap (whole wheat tortilla, vegan mayo, tempeh slices, Frank’s Red Hot Sauce, tomato slices, shredded lettuce)

• Tofu Spring Rolls (seasoned tofu to taste, spring roll wrapper, shredded savoy cabbage, shredded carrots, cilantro or mint + peanut ginger soy sauce for dipping)

• Cold Vermicelli Noodle Salad (vermicelli noodles, cucumbers, shredded carrots, thinly sliced bell peppers, cilantro or mint + sauce [soy sauce, agave, chili flakes, ginger])


Food and Nutrition Board, Institute of Medicine, National Academies. (2011). Dietary Reference Intakes (DRIs): Recommended Dietary Allowances and Adequate Intakes, Elements. Retrieved from National Institutes of Health: Office of Dietary Supplements [source]

Food and Nutrition Board, Institute of Medicine, National Academies. (2011). Dietary Reference Intakes (DRIs): Recommended Dietary Allowances and Adequate Intakes, Total Water and Macronutrients. Retrieved from National Institutes of Health: Office of Dietary Supplements [source]

Thalheimer, J. (2014, April). The Top 5 Soy Myths. Retrieved from Today’s Dietitian: The Magazine for Nutrtion Professionals [source]

Messina, G. (2011, August). Soy Isoflavones and Estrogen. Retrieved from The Vegan RD [source]

Norris, J. (2011, April). Soy Part 1 – Main Controversies. Retrieved from [source]

*Karla Moreno-Bryce, MDA, RD, LD is a Registered Dietitian and a Licensed Dietitian. She obtained a Bachelor of Arts in Physical Anthropology through the University of California Santa Barbara while studying to go to medical school. She later went on to obtain a post-baccalaureate in Nutrition & Dietetics at Cal Poly Pomona. She completed a Dietetic Internship through Utah State University and also obtained a Masters of Dietetic Administration. She is credentialed through the Commission on Dietetic Registration. Karla is also fluent in Spanish.
Professional Affiliates and Memberships:
-Licensed Dietitian in the state of Minnesota
-Academy of Nutrition and Dietetics (AND)
-Nutrition Entrepreneurs Dietetic Practice Group
-Vegetarian Nutrition Dietetic Practice Group
-Certificate of Training in Vegetarian/Vegan Nutrition
-2016-2017 National Nutrition Month Chair for California Academy of Nutrition and Dietetics – Coastal Tri Counties

Visit NutritiousVida and follow Karla Moreno-Bryce, MDA, RD, LD @nutritiousvida.

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