As controversial as the nutrition world can be, most people agree that eating more plants is a good idea. Loaded with antioxidants, fiber, and essential nutrients, the merits of a plant-based diet are difficult to ignore.
Well-planned vegan and vegetarian eating patterns can provide all of the nutrients your body needs to thrive. But “well-planned” is the operative phrase, because certain nutrients can be difficult to find exclusively in plant-based foods.
A bit of forethought and careful incorporation of fortified foods and supplements may be necessary to ensure you’re meeting your nutrition needs on these kinds of diets.
Here we’ll explore several nutrients that are often lacking in vegan and vegetarian diets, including the best ways to obtain them—be it through food or supplements.
1. Vitamin B12
Vitamin B12 is an essential nutrient that is critical for many of your body’s most basic functions including red blood cell formation, energy production, and DNA synthesis (1).
The Recommended Dietary Allowance (RDA) for vitamin B12 for adults is 2.4mcg per day. Unfortunately, this particular vitamin doesn’t naturally exist in large enough quantities in plant-based foods to meet this mark, putting vegans and vegetarians at particularly high risk for developing a deficiency (2, 3).
If you adhere to a lacto-ovo vegetarian diet, you can easily get B12 from dairy and egg products, but fortified foods and/or supplements are necessary for anyone following a more restrictive vegetarian or vegan diet.
Fortunately there are a wide variety of B12 fortified foods available including most commercially produced breakfast cereals, some plant-based milk and yogurt alternatives, nutritional yeast, and most vegetarian meat alternatives.
Note that not all plant-based meat and dairy alternatives have B12 added. Be sure to check the nutrition facts panel and ingredient list on the particular product to verify.
You can also meet your B12 needs with over the counter or prescription vitamin supplements. The most common supplemental forms of B12 are cyanocobalamin and methylcobalamin—both of which are good options. Just make sure whichever supplement you choose has been tested by a third party to ensure the highest quality (2).
Keep in mind that your body won’t absorb 100% of the B12 you consume in a supplement and some people may require doses larger than the RDA to meet their needs. One study found that doses as high as 6mcg per day may be most appropriate for vegans—especially if no B12-fortified foods are included in the diet (4).
2. Vitamin D
Vitamin D is a nutrient that is essential for bone health and proper immune function. Currently, the RDA for vitamin D is set at 600IU per day for adults up to 70 years of age and bumps up to 800IU per day for anyone older than that. However, some health authorities assert that daily intakes should be closer to 1500-2000IU (5, 6).
Many people have trouble consuming enough vitamin D, even if animal-based foods are included in their diet.
Oddly enough, the best way to get vitamin D is not from food at all— it’s from the sun. When your skin is exposed to UV radiation from sunlight, it produces its own vitamin D (7).
However, there are many factors that can limit your skin’s ability to make vitamin D, including too much time spent inside, sunscreen use, level of skin pigmentation, and geographical location. Thus, if you routinely use sunscreen, don’t go outside often, have darker skin, or live in a place far away from the equator, you have to make sure to get your vitamin D from food or supplements (7).
The only major plant-based food source of vitamin D is mushrooms, but the exact amount of vitamin D in any given mushroom can vary tremendously. Much like humans, mushrooms make vitamin D when exposed to sunlight. For this reason, wild mushrooms are typically higher in vitamin D than their farmed counterparts. Although some brands of farmed mushrooms treat their product with UV light to boost the vitamin D content before sending it to market (8).
Fortified foods and supplements are also great options. Breakfast cereals, orange juice, and plant-based milk and yogurt alternatives are often fortified with vitamin D—simply check the nutrition facts labels to know how much is added.
If you’re planning to take a supplement, the best and most effective form of vitamin D is D3. However, the majority of D3 supplements are animal-based. Thus, if you’re a vegan or strict vegetarian, you’ll want to make sure you choose one that has been sourced exclusively from plants, such as Nordic Naturals Vegan D3.
3. Vitamin K2
Vitamin K1, a nutrient frequently found in dark leafy greens, has long been known for the pivotal role it plays in blood clotting. But more recently, the importance of a different form of the vitamin— vitamin K2—has come to light.
Research indicates that vitamin K2 is essential for maintaining bone and dental health. Emerging data further suggests that vitamin K2 may also play a role in preventing heart disease and certain types of cancer (9).
The majority of vitamin K in a typical Western diet is K1, a small proportion of which can be converted to K2 in your body. Small quantities of vitamin K2 can also be produced by the bacteria living in your gut (10).
The richest dietary K2 sources are animal-based foods such as whole milk, cheese, and egg yolks. That said, certain fermented plant-based foods—such as sauerkraut, miso, and natto—also contain some K2. These foods are widely available, but tend to be less prevalent in dietary patterns in the United States (10).
In terms of dietary recommendations, vitamins K1 and K2 are still usually grouped together as simply “vitamin K.” The RDA for vitamin K currently remains at 120mcg per day for men and 90mcg per day for women, although some experts think separate recommendations should be made for vitamin K2. Until that happens, there is no clearly defined dose for vitamin K2 (11).
In order to make sure you’re getting enough K2 on a vegan or vegetarian diet, start by making sure you’re meeting the minimum recommendations for vitamin K. This shouldn’t be too hard as vitamin K is found in a variety of fruits and vegetables such as kale, spinach, brussels sprouts, kiwi, and avocado.
Next, work on incorporating more fermented foods—like miso, natto, kimchi, and sauerkraut—into your routine. Not only do fermented foods contain K2, but their probiotic content may also help to support healthy gut bacteria, some of which can produce additional K2 for you (11).
If you want to go the supplement route, two separate multi-year studies in post-menopausal women found that daily supplementation with 180mcg vitamin K2 in the form of MK-7 had a positive effect on bone and heart health. MK-7 is easily absorbed and stays in the system longer than other forms of K2, thus, is probably your best supplement option (9).
If you are taking any blood thinning medications, consult your healthcare provider before adding any kind of vitamin K supplements to your regimen.
Iodine is a mineral your body needs to produce an adequate supply of thyroid hormones which regulate energy metabolism. It is also critical for fetal brain development (12).
Iodine deficiency is rare in the United States thanks to the introduction of iodized salt, but insufficient intake is still very prevalent in many other parts of the world.
To potentially make matters worse, many people in the United States are now opting for non-iodized salt sources, such as Kosher and sea salt, which could lead to insufficient intake if you’re not taking care to include plenty of other iodine-rich foods on your plate.
All in all, humans don’t need very much iodine. The RDA is set at 150mcg for adults, almost half of which can be provided by just ¼ teaspoon of iodized salt (13).
Some of the richest natural sources of iodine are animal-based foods, but there are plenty of plant-based iodine sources, too.
The main concern with plant-based iodine food sources is that their iodine content is dependent on the iodine content of the soil in which they’re grown. This means there can be tremendous variability in the total quantity of iodine within the same types of food, depending on where and how they’re grown (13).
Seaweed (nori, kelp, kombu), whole grain bread, lima beans, and prunes are among the richest sources of plant-based iodine. If you don’t routinely use iodized salt when you cook, make sure to include these foods frequently to ensure adequate intake.
If you’re not able to get enough iodine from food, supplements may be a good option.
That said, proceed with supplementation cautiously because too much can cause the same thyroid issues that inadequate intakes cause. To avoid toxic effects, the National Institute of Health recommends that adults do not exceed 1100mcg of iodine from food or supplements (13, 14).
Iron is a mineral that is essential for red blood cell formation and transport of oxygen throughout the body (15).
Iron deficiency remains one of the most common nutrient deficiencies worldwide. Those following strict vegan and vegetarian diets may be at greater risk for low iron than people who consume animal-based foods due to differences in the types of iron in plants vs animals (16).
Heme-iron is the form of iron in meat and other animal-based foods, whereas non-heme iron is the form found in plants. Heme-iron is more easily absorbed than non-heme iron so when animal sources of iron are eliminated from the diet, it can be more difficult to obtain adequate amounts of this vital mineral. Because of this, it’s recommended that those following vegetarian and vegan diets consume twice the RDA for iron— 36mg for adult women up to 50 years old, and 16mg for adult men. Women over 50 only need 16mg per day (17).
That said, there are many different plant-based foods that contain iron and if you eat a varied diet, meeting your iron needs shouldn’t be too difficult. Legumes, nuts, seeds, whole grains, spinach, collard greens, and swiss chard are all great plant-based iron sources.
You can boost your body’s absorption of non-heme iron by pairing it with a source of vitamin C. For example— squeeze some fresh lemon juice over a spinach salad, have a broccoli and bell pepper slaw with your lentil soup, or add sliced strawberries to your morning oatmeal.
Another thing to be mindful of is your intake of tannins. Tannins are compounds found in some plant-based foods that can bind to iron, rendering in unavailable for absorption in the GI tract. Thus, you should avoid consuming tannin-rich foods with meals that contain iron. Tea, wine, coffee, and chocolate are among some of the richest sources of tannins. If you enjoy these foods, just have them in between meals instead of with them to maximize iron absorption at meal times (18).
If you consume a varied diet and follow these tips but still have persistently low iron levels, a supplement may be necessary. Talk to your healthcare provider before starting any iron supplementation on your own, as you may need a dose much higher than the RDA, depending on the severity of your deficiency.
Keep in mind that iron supplements can cause constipation, so make sure to stay hydrated and eat plenty of fiber if you start supplementing.
Calcium is absolutely essential for bone health, but it also helps regulate the contraction of cardiac and skeletal muscles.
The RDA for calcium is 1000mg per day for women up to 50 years old and 1200mg per day for women over 50. For men it’s 1000mg per day up to age 70, and 1200mg per day for men over age 70 (19).
Dairy products—like milk, cheese, and yogurt—are one of the top sources of calcium in Western diets. But if you’re following a vegan or ovo-vegetarian diet, dairy-based calcium isn’t in the cards (19).
Fortunately, that’s not a problem because there are lots of plant-based foods that you can use to meet your calcium needs instead.
Tofu, almonds, sesame seeds, broccoli, cabbage, kale, and calcium-fortified cereals, juices, and dairy-alternatives are all great options.
If you’re new to a vegan or vegetarian lifestyle, you may notice that plant-based calcium isn’t always a very concentrated source of the mineral, especially compared to dairy products. Thus, you may need to include extra servings and a wider variety of foods to meet your needs.
If you’re not able to get enough calcium with food alone, you may want to consider taking a calcium supplement. Often calcium supplements are paired with vitamin D because calcium cannot be properly absorbed without adequate vitamin D. But be careful not to take too much, as it could increase your risk for developing kidney stones or calcium deposits in blood vessels (20).
Most people don’t need to consume more than the RDA between food and supplements, but if you’re unsure how much you should take, consult your healthcare provider.
Zinc is a mineral that plays an important role in immunity, growth, and tissue repair (21).
The RDA for zinc is 11mg for men and 8mg for women (22).
Zinc is present in a variety of plant-based foods such as legumes, grains, nuts, and seeds. However, it’s not very well absorbed from these foods due to the presence of phytates. Phytates bind to zinc rendering it unavailable for absorption within the digestive tract. Because of this, its recommended that people following strict vegan diets consume 50% more than the RDA, or 16.5mg for men and 12mg for women (22).
Soaking and sprouting legumes, grains, and seeds can help reduce the phytate content and improve zinc absorption (21).
It can be difficult to assess an individual’s zinc status, but symptoms of deficiency include delayed wound healing, poor immune function, hair loss, and diarrhea (22).
If you think you’re not getting adequate zinc from you diet, supplements in the form of zinc gluconate or zinc sulfate are good options.
Zinc toxicity is a possibility, so make sure you don’t take too much. The upper limit is set at 40mg per day for men and women, although there’s really no reason to take this much unless you’ve been explicitly instructed to do so by your doctor (22).
Choline is an essential nutrient that the majority of people living in the United States aren’t getting enough of—regardless of the kind of diet they follow. Thus, it’s no surprise that it frequently gets overlooked when planning vegan and vegetarian diets, too.
Choline has many different functions, but one of its main roles is in the production of an important neurotransmitter called acetylcholine. Acetylcholine is required for proper brain development, memory, and muscle control (23).
Adequate intake of choline is currently set at 550mg per day for men and 425mg per day for women (23).
Choline is present in a variety of plant-based foods, but not in particularly high amounts. Thus, a highly varied diet is important for meeting the choline needs of people who don’t consume any animal products.
Soy beans, potatoes, quinoa, and kidney beans are among the richest plant-based choline sources, but other veggies and grains such as cabbage, brown rice, and green peas provide small amounts too.
If you follow an ovo-vegetarian diet, a single egg can provide 27% of the daily recommended amount of choline.
If you suspect you’re not getting enough choline in your diet, a supplement may be worth considering.
Choline is available as a stand-alone supplement, but it is also usually incorporated into multivitamin formulations. However, like many other supplements, too much of a good thing can lead to negative consequences.
Excess choline intake can increase your production of a compound known as TMAO. Elevated levels of TMAO are associated with increased risk for heart disease. To avoid any major adverse effects, its best to avoid exceeding 3500mg of choline from food and supplements (23).
9. Omega-3 Fats
Omega-3 fats are a particular type of fat with a variety of beneficial anti-inflammatory functions (24).
Only two fatty acids are considered nutritionally essential and one of them happens to be an omega-3 known as ALA, or alpha-linolenic acid.
ALA is prevalent in a variety of plant-based foods such as walnuts, chia seeds, hemp seeds, and flax seeds.
With careful planning it’s relatively easy for vegans and vegetarians to get plenty of ALA, but there are two other important omega-3’s that are substantially more difficult to obtain.
ALA is metabolically converted to EPA and DHA in your body. EPA and DHA are two types of omega-3’s that are vital for brain and eye health across the lifespan (25).
Because they can be made from ALA, they’re not considered “essential.” However, the conversion of ALA to EPA and DHA is very inefficient—possibly as low as 5% (25).
Therefore, it’s important to get these fats from other sources. The only major food sources of EPA and DHA are animal-based, so if you’re vegan or strictly vegetarian, a supplement may be necessary.
Note that most EPA/DHA supplements are derived from fish and aren’t appropriate for vegans. Instead, look for high quality vegan versions sourced from algae. A daily dose 200-300mg combined EPA and DHA is likely sufficient for most people, especially when paired with a diet rich in ALA (26).
Protein is usually considered the most challenging macronutrient to obtain on vegetarian and vegan diets, especially for people who have particularly high protein needs—such as athletes, older adults, or people battling acute and chronic illnesses.
While it is entirely possible to meet protein needs on an animal-free diet, some people are surprised by the volume of food required to do so when they’re first transitioning to a more plant-based lifestyle.
Legumes, nuts, seeds, and whole grains are among the richest sources of plant-based protein, however, the majority of them aren’t considered “complete” proteins.
Complete proteins are proteins that contain all 9 essential amino acids your body needs to carry out basic, vital functions.
Certain plant-based proteins, such as soy beans and hemp seeds, are considered complete, but many of the others have to be combined to form complete proteins. In order to avoid any amino acid deficiencies, focus on including a wide variety of plant-based protein sources in your menus.
The absolute minimum amount of protein you need is about 0.8 grams of protein kilogram of bodyweight. That said, most people will probably do better with 1-1.5 grams of protein per kilogram of bodyweight. In some cases, up 2 grams may be most appropriate (27).
If you have difficulty meeting your protein needs with diet alone, protein powders are a great way to boost your intake. Mix protein powder into smoothies, stews, sauces, or quick bread batters for an easy way to increase the protein content of your favorite foods.
These days vegan protein powders are made from many different sources including soybeans, peas, brown rice, pumpkin seeds, and hemp seeds. They also come in a variety of flavors to suit your tastes.
When you’re shopping for a protein powder, choose one with high quality ingredients and avoid those with lots of added sugar. Note those made from legumes and grains tend to be more affordable than the ones made from seeds.
Making the Most of Your Diet
Vegan and vegetarian diets come with a variety of health benefits, but without proper planning, it can be easy to miss out on some vital nutrients.
Often times the solution is as simple as throwing a few new foods into your menu rotation or adding a multivitamin to cover the gaps.
If you’re new to a vegetarian or vegan lifestyle, remember to not only focus on what you’re removing, but also what you’re adding back in. This way you’ll get the most out of your diet while ensuring your body still has all of the tools it needs to thrive.
Feature photo: ID 45307223 © Niloo138 | Dreamstime