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Doctor debunks plant-based diet myths

Written By: Andi Atkinson, UT Physicians | Updated: March 28, 2023
Two young adults eat salad at the gym.

Contrary to what some believe, a plant-based diet provides enough protein, calcium, and iron for all people.

Though many people have heard of a plant-based diet, most have never attempted the lifestyle due to some common misconceptions.

Pritesh Mutha, MD
Pritesh Mutha, MD

For National Nutrition Month, Pritesh Mutha, MD, gastroenterologist with UT Physicians and associate professor of gastroenterology, hepatology, and nutrition with McGovern Medical School at UTHealth Houston, debunks the five greatest myths of a plant-based diet.

Myth 1

A plant-based diet doesn’t provide enough protein.

“People believe they need to receive their protein from animals or animal products like dairy and eggs, but if you think about it this way: Where did the cows, chickens, and other animals get their protein from? They get their protein from eating plants,” Mutha said.

Every plant-based food contains some protein.

“It’s best to get your protein directly from the source,” Mutha said. “Even many world-class athletes meet their protein requirements from a plant-based diet.”

“Studies have shown that intake of animal protein can increase the risk of certain cancers, heart disease, kidney disease, and bone disorder,” Mutha said. “There’s a lot of research that shows whole plant-based protein food sources help reverse various diseases.”

Myth 2

A plant-based diet doesn’t provide enough calcium.

“It’s believed you need to consume dairy for stronger bones,” Mutha said, “but a study on the consumption of dairy and osteoporosis (a condition that weakens bones) showed that  post-menopausal women from countries that consumed higher amounts of dairy had an even higher rate of fractures.”

“It’s completely paradoxical to what we’ve always been taught about getting calcium from dairy,” he added.

It is easily possible to obtain the necessary calcium requirement from plant-based foods.

“Plant-based foods have plenty of calcium in them. Green vegetables and seeds, especially, can be excellent sources of calcium,” Mutha said. “Moreover, 10 minutes of direct sunlight a day without any sunscreen will provide the vitamin D necessary for bone health and multiple other essential bodily functions.”

A vitamin D supplement can help strengthen bones for those who do not receive ample sunshine.

Despite a predominantly animal-based diet, more than 40% of Americans are deficient in vitamin D. A simple blood test can be used to check for vitamin D deficiency.

Myth 3

A plant-based diet doesn’t provide enough vitamin B12.

“Lack of B12 is not uncommon. Even people consuming animal products often have a B12 deficiency,” Mutha said. “B12 is not produced by animals but by bacteria from the soil. As fewer animals are grass-fed, the B12 they pass on can be very low. Many dairy farm animals are actually fed vitamin B12 supplements.”

A B12 supplement can support a healthy central nervous system and the growth of red blood cells and DNA. Mutha recommends B12 supplements for nearly everyone.

Myth 4

A plant-based diet will cause bloating and gas.

“Until your body adapts to a plant-based diet, you may feel bloating and gas for about two weeks,” Mutha said, “but this will start getting better as soon as good bacteria starts flourishing in your gut.”

The lack of fiber is the reason many people have constipation, which can result in bloating, gas, abdominal pain, and gastrointestinal problems.

“Fiber provides roughage for normal bowel movements and decreases your cholesterol levels. The more the better! All the more, it’s a vehicle to get rid of toxins and excess toxic hormones from your body.”

Unlike a plant-based diet, the standard American diet of animal products and processed foods is fiber-deficient.

“It doesn’t meet the minimum recommended fiber requirement — 25 grams a day for women, 38 grams for men. Only 3% of Americans get their daily fiber requirement,” he said.

For a healthier gut that reduces gastrointestinal issues, it is better to get fiber from whole-food plants than supplements.

“The inner lining of your gut loves fiber from whole foods. The good bacteria in your gut thrives on fiber,” Mutha said. “On the other hand, processed foods and chemicals multiply the bad bacteria and weaken your gut. This leads to diseases.”

Myth 5

A plant-based diet doesn’t provide enough iron.

“There are two types of iron in foods, the heme and the non-heme fraction,” Mutha said. “Heme iron is primarily in red meat. Non-heme is mainly in plants, especially whole grains, legumes, and some vegetables. People can fulfill their daily iron requirement from a whole-food, plant-based diet.”

Plant-based foods can provide sufficient iron in a healthier form than meat.

The body absorbs heme iron more quickly, but excess heme can potentially increase the risk of cancer in two ways: 1) It can cause free radicals that damage DNA; and 2) It can cause N-nitroso compounds, which are carcinogenic (cancer-causing).

“Our body can better control the absorption of iron from plant sources better than animal sources, helping avoid the damaging effects of excess iron,” Mutha said. “Meats also don’t have phytonutrients, which neutralize the effects of damaging free radicals that cause cancer and other diseases.”

Vitamin C, especially from citrus fruits and cruciferous vegetables, can help the body absorb safer, non-heme iron. Dairy products, eggs, coffee, and alcohol block absorption.

Consult with a physician before starting any new diet or taking dietary supplements.

As the clinical practice of McGovern Medical School at UTHealth Houston, UT Physicians has locations across the Greater Houston area to serve the community. To schedule an appointment, call 888-4UT-DOCS.