Understanding Nutrient Deficiencies in Plant-Based Diets
Have you ever heard someone say they quit veganism because they felt unhealthy? These stories often spread like wildfire, casting doubt on the vegan lifestyle. But here’s the truth: the problem isn’t veganism—it’s a lack of knowledge about proper nutrition.
The reality is, a well-planned vegan diet can be one of the healthiest choices you’ll ever make. However, like any diet, it requires attention to detail. Vegans who educate themselves, embrace variety, and supplement wisely often thrive far better than their non-vegan counterparts. Why? Because plant-based foods are naturally lower in harmful saturated fats, cholesterol, and inflammatory compounds while being packed with fiber, antioxidants, and essential nutrients.
But let’s address the elephant in the room: Why do vegans need to supplement if their diet is so healthy? The answer lies in understanding which nutrients are harder to obtain from plants and how to bridge those gaps effectively.
The 6 Critical Nutrients Vegans Need to Watch
While a vegan diet is rich in many nutrients, there are six key nutrients that are more abundant in animal products. Here’s what they are, why they matter, and how you can get them without compromising your vegan values:
Vitamin B12: The Non-Negotiable Supplement
Vitamin B12 is essential for nerve function and red blood cell production. Historically, humans obtained B12 from soil and untreated water, but modern sanitation practices have eliminated these sources. Today, farmed animals are supplemented with B12, which is why it’s abundant in animal products.
Key Points:
- Daily Requirement: 2.4 mcg for adults.
- Plant-Based Sources: Fortified nutritional yeast, plant milks, and breakfast cereals.
- Supplementation: Since fortified foods may not provide consistent levels, a B12 supplement is highly recommended for vegans.
The highest natural sources of vitamin B12 are contained in animal foods – however, certain plant-based sources are fortified (vitamins added) with B12 such as certain brands of nutritional yeast, breakfast cereals and plant milks. The highest sources of B12 are contained in the following foods:
*DV = Daily Value. FDA developed DVs to help consumers compare the nutrient contents of foods and dietary supplements within the context of a total diet.
Vitamin D3: The Sunshine Vitamin (That’s Hard to Get)
The recommended daily allowance for vitamin D3 for adults up to 70 years of age is 15 micrograms (mcg) / 600 international units (IU).
Vitamin D3 is vital for bone health, immune function, and calcium absorption. While sunlight is a natural source, factors like geographic location, skin tone, and sunscreen use can limit its effectiveness.
Key Points:
- Daily Requirement: 15 mcg (600 IU) for adults up to 70 years.
- Plant-Based Sources: Fortified plant milks, UV-exposed mushrooms, and supplements.
- Sunlight Exposure: Aim for 10–30 minutes of midday sun, but balance this with skin cancer prevention measures.
*DV = Daily Value. FDA developed DVs to help consumers compare the nutrient contents of foods and dietary supplements within the context of a total diet.
Non-vegans would normally get their D3 in common food sources such as trout, salmon and milk. It is a fat-soluble vitamin and would be best absorbed in the body with a healthy fat source. Vitamin D also promotes calcium absorption.
VITAMIN D FROM THE SUN
Your body can produce Vitamin D if it is exposed to direct sunlight. It is recommended that we get 10 – 30 minutes of midday sun exposure as the body is most efficient at making vitamin D at noon. Sun exposure depends on the season and distance from the equator. More sun exposure is required in winter than in summer to get the required level of vitamin D.
Sun exposure also comes with certain skin cancer risks, so it is important to not unnecessarily over-expose yourself. It is important and recommended my dermatologists that we wear sunscreen during the day to protect our skin from UVA and UVB rays.
While sunlight exposure can help synthesize Vitamin D, factors like geographic location, skin pigmentation, and sunscreen use can affect this process. Therefore, fortified foods or supplements might be necessary, especially during months with limited sunlight.
Omega-3 Fatty Acids: The Brain-Boosting Essential
Omega 3’s can be broken down into the short chain fatty acids (ALA) and the long chain fatty acids (EPA and DHA). Vegans can easily obtain the omega 3 short chain fatty acids from nuts and seeds but the long chain fatty acids (EPA and DHA) are obtained from sea vegetables which are less common foods in one’s diet.
While ALA is found in plant sources like flaxseeds and walnuts, its conversion to EPA and DHA is limited. Therefore, incorporating algae-based supplements can ensure adequate levels of these essential fatty acids.
The recommended daily allowance for the long chain Omega 3 is 250–500 mg combined EPA and DHA.
Omega 3’s can be obtained from the following food sources:
| Table 2: ALA, EPA, and DHA Content of Selected Foods [29] | |||
| Food | Grams per serving | ||
| ALA | DHA | EPA | |
| Flaxseed oil, 1 tbsp | 7.26 | ||
| Chia seeds, 1 ounce | 5.06 | ||
| English walnuts, 1 ounce | 2.57 | ||
| Flaxseed, whole, 1 tbsp | 2.35 | ||
| Salmon, Atlantic, farmed, cooked, 3 ounces | 1.24 | 0.59 | |
| Salmon, Atlantic, wild, cooked, 3 ounces | 1.22 | 0.35 | |
| Herring, Atlantic, cooked, 3 ounces* | 0.94 | 0.77 | |
| Canola oil, 1 tbsp | 1.28 | ||
| Sardines, canned in tomato sauce, drained, 3 ounces* | 0.74 | 0.45 | |
| Mackerel, Atlantic, cooked, 3 ounces* | 0.59 | 0.43 | |
| Salmon, pink, canned, drained, 3 ounces* | 0.04 | 0.63 | 0.28 |
| Soybean oil, 1 tbsp | 0.92 | ||
| Trout, rainbow, wild, cooked, 3 ounces | 0.44 | 0.4 | |
| Black walnuts, 1 ounce | 0.76 | ||
| Mayonnaise, 1 tbsp | 0.74 | ||
| Oysters, eastern, wild, cooked, 3 ounces | 0.14 | 0.23 | 0.3 |
| Sea bass, cooked, 3 ounces* | 0.47 | 0.18 | |
| Edamame, frozen, prepared, ½ cup | 0.28 | ||
| Shrimp, cooked, 3 ounces* | 0.12 | 0.12 | |
| Refried beans, canned, vegetarian, ½ cup | 0.21 | ||
| Lobster, cooked, 3 ounces* | 0.04 | 0.07 | 0.1 |
| Tuna, light, canned in water, drained, 3 ounces* | 0.17 | 0.02 | |
| Tilapia, cooked, 3 ounces* | 0.04 | 0.11 | |
| Scallops, cooked, 3 ounces* | 0.09 | 0.06 | |
| Cod, Pacific, cooked, 3 ounces* | 0.1 | 0.04 | |
| Tuna, yellowfin, cooked 3 ounces* | 0.09 | 0.01 | |
| Kidney beans, canned, ½ cup | 0.1 | ||
| Baked beans, canned, vegetarian, ½ cup | 0.07 | ||
| Ground beef, 85% lean, cooked, 3 ounces** | 0.04 | ||
| Bread, whole wheat, 1 slice | 0.04 | ||
| Egg, cooked, 1 | 0.03 | ||
| Chicken, breast, roasted, 3 ounces | 0.02 | 0.01 | |
| Milk, low-fat (1%), 1 cup | 0.01 | ||
*Except as noted, the U.S. Department of Agriculture (USDA) database does not specify whether fish are farmed or wild caught.
**The USDA database does not specify whether beef is grass fed or grain fed.
The highest sources of the short chain omega 3 (ALA) are from plant sources but it is easier to get the long-chain fatty acids (EPA and DHA) from animal foods, particularly seafood. Vegans would need to supplement with Algal oil or consume uncommon plant-based sources such as seaweed or algae to get the recommended daily intake of EPA and DHA.
Calcium: Building Strong Bones the Vegan Way
The daily recommended allowance for calcium is:
| Food | Milligrams (mg)per serving | Percent DV* |
| Yogurt, plain, low fat, 8 ounces | 415 | 32 |
| Orange juice, calcium fortified, 1 cup | 349 | 27 |
| Yogurt, fruit, low fat, 8 ounces | 344 | 27 |
| Mozzarella, part skim, 1.5 ounces | 333 | 26 |
| Sardines, canned in oil, with bones, 3 ounces | 325 | 25 |
| Milk, nonfat, 1 cup** | 299 | 23 |
| Soymilk, calcium fortified, 1 cup | 299 | 23 |
| Milk, whole (3.25% milk fat), 1 cup** | 276 | 21 |
| Tofu, firm, made with calcium sulfate, ½ cup*** | 253 | 19 |
| Salmon, pink, canned, solids with bones, 3 ounces | 181 | 14 |
| Cottage cheese, 1% milk fat, 1 cup | 138 | 11 |
| Tofu, soft, made with calcium sulfate, ½ cup*** | 138 | 11 |
| Soybeans, cooked, ½ cup | 131 | 10 |
| Breakfast cereals, fortified with 10% of the DV for calcium, 1 serving | 130 | 10 |
| Spinach, boiled, drained, ½ cup | 123 | 9 |
| Frozen yogurt, vanilla, soft serve, ½ cup | 103 | 8 |
| Turnip greens, fresh, boiled, ½ cup | 99 | 8 |
| Kale, fresh, cooked, 1 cup | 94 | 7 |
| Chia seeds, 1 tablespoon | 76 | 6 |
| Chinese cabbage (bok choi), raw, shredded, 1 cup | 74 | 6 |
| Beans, pinto, canned, drained, ½ cup | 54 | 4 |
| Tortilla, corn, one, 6” diameter | 46 | 4 |
| Sour cream, reduced fat, 2 tablespoons | 31 | 2 |
| Bread, whole wheat, 1 slice | 30 | 2 |
| Kale, raw, chopped, 1 cup | 24 | 2 |
| Broccoli, raw, ½ cup | 21 | 2 |
| Apple, golden delicious, with skin, 1 medium | 10 | 0 |
* DV = Daily Value. The U.S. Food and Drug Administration (FDA) developed DVs to help consumers compare the nutrient contents of foods and dietary supplements within the context of a total diet. The DV for calcium is 1,300 mg for adults and children age 4 years and older [13]. FDA requires food labels to list calcium content. Foods providing 20% or more of the DV are considered to be high sources of a nutrient, but foods providing lower percentages of the DV also contribute to a healthful diet.
** Calcium content varies slightly by fat content; the more fat in the food, the less calcium it contains.
*** Calcium content is for tofu processed with a calcium salt. Tofu processed with other salts does not provide significant amounts of calcium.
There are plenty of healthy plant-based sources of calcium such as tofu, soybeans, leafy greens, chia and sesame seeds as well as various fortified foods. The healthy plant-based sources of calcium also come packed with many other nutrients and fibre compared to the risks of dairy-based calcium, which includes saturated fat as well as hormones from the animal.
Iodine: The Overlooked Nutrient
The recommended daily allowance for Iodine is:
The highest food sources of Iodine are:
*DV = Daily Value. FDA developed DVs to help consumers compare the nutrient contents of foods and dietary supplements within the context of a total diet.
Unless vegans have access to foods such as iodate dough bread, seaweed, kelp or iodized salt, there aren’t many common plant-based foods to get this nutrient. The good news is that iodine is contained in most multivitamins and is relatively cheap as a supplement.
Iodine content in plant foods can vary based on soil content. Therefore, using iodized salt or taking a supplement can help meet daily requirements.
Zinc: The Immune System’s Best Friend
The daily recommended daily allowance for Zinc is:
The top food sources of Zinc are as follows:
*DV = Daily Value. FDA developed DVs to help consumers compare the nutrient contents of foods and dietary supplements within the context of a total diet.
Plant-based sources of zinc include pumpkin seeds, lentils, peanuts and kidney beans, whereas the animal-based sources generally have a higher concentration of zinc.
Why Supplementation Isn’t a Weakness—It’s a Strength
Let’s get one thing straight: supplementing doesn’t mean your diet is lacking—it means you’re taking control of your health. Even non-vegans often fall short on key nutrients, but vegans have the unique advantage of being more mindful about their nutritional intake.
Here’s the bottom line: A well-planned vegan diet, combined with strategic supplementation, can be one of the healthiest ways to live. By addressing potential nutrient gaps, you’re not just surviving—you’re thriving.
Your Vegan Supplement Checklist
To make it easy, here’s a quick guide to the supplements every vegan should consider:
- Vitamin B12: A must-have for nerve and blood health.
- Vitamin D3: Essential for bone health and immunity.
- Omega-3 (EPA/DHA): For brain and heart health.
- Iodine: Supports thyroid function.
- Zinc: Boosts immunity and healing.
Vegans Do Not Need to Supplement Their Protein
Yes, animal-based protein on average has a higher concentration per 100g of protein than plant-based sources, but there are still plenty commonly available plant-based sources of protein for vegans to obtain without any supplementation. Some of the common high protein vegan food sources include:
- Seitan
- Pea protein
- Peanut butter
- Tempeh
- Edamame
- Oats
- Tofu
- Red lentils
- Chickpeas
- Peas
- Quinoa
The recommended daily general guideline for protein requirement is based on 0.8 grams per kilogram of lean body weight.
Example: an 80kg person with 20% body fat requires protein as follows:
- Calculate lean body mass: 80kg less 20% body fat = 64kg lean mass
- Lean body mass of 64kg x 0.8 grams of protein required = 51.2 grams required per day.
As an example, two slices of wholewheat toast with peanut butter would give you about 18 grams of protein which is already 35% of your protein needs in one meal.
Why Do Most Bodybuilding Programs Recommend Animal Protein For Muscle Growth?
Most animal foods provide more protein per calorie than plant-based sources. This allows bodybuilders to obtain more protein by consuming fewer calories. Animal protein, however, comes with many risks. Bodybuilders consuming excessive protein to grow their muscles are often focused on their short-term muscle gains by putting their health at risk. This gets overlooked because their muscular physique misleads them into believing they are healthy. Animal protein has been linked to heart disease and cancer.
Obtaining protein from plants might result in it taking a little longer to achieve one’s bodybuilding goals due to the higher carbohydrate content of plant foods, but this would be a much safer option to protect your health.
Swapping Out The Animal Protein For Plant-Based Sources
Let’s do a rough comparison based on the main protein sources and the nutrients listed above:
| ANIMAL BASED SOURCES | Protein (g) | Vitamin B12 (µg) | Calcium (mg) | Vitamin D3 (µg) | Omega-3 (g) | Iodine (µg) | Zinc (mg) |
| 2 Large Hard Boiled Jumbo Eggs | 13 | 1.3 | 25 | 1.1 | 0.1 | 27 | 1.3 |
| 2 Cooked Chicken Breasts | 54 | 0.6 | 13 | 0 | 0 | 0 | 2.4 |
| Half a Cup Of Unsweetened Dairy Yogurt | 5 | 1 | 183 | 2.5 | 0 | 0 | 0.8 |
| 100 grams of Cheddar Cheese | 25 | 0.8 | 721 | 0.5 | 0.01 | 15 | 3.1 |
| TOTAL | 97 | 3.7 | 942 | 4.1 | 0.11 | 42 | 7.6 |
| VEGAN SOURCES | Protein (g) | Vitamin B12 (µg) | Calcium (mg) | Vitamin D3 (µg) | Omega-3 (g) | Iodine (µg) | Zinc (mg) |
| Half A Can of Chickpeas | 7.3 | 0 | 50 | 0 | 0.1 | 22 | 1.3 |
| Half A Block of Firm Tofu | 10 | 0 | 138 | 0 | 0.3 | 30 | 1.8 |
| 100 grams of Rolled Oats | 16.9 | 0 | 52 | 0 | 0.15 | 0 | 4 |
| 100 grams of Peanut Butter | 25 | 0 | 51 | 0 | 0.01 | 0 | 2.5 |
| Half a Can of Kidney Beans | 7.7 | 0 | 45 | 0 | 0.05 | 9 | 0.8 |
| 50 grams of fortified Nutritional Yeast | 25 | 6 | 500 | 0 | 0 | 0 | 1 |
| TOTAL | 92.9 | 6 | 836 | 0 | 0.51 | 61 | 11.6 |
As we can see, vegans are getting almost the same amount of protein from plant-based sources, but could be lacking in some of the other nutrients which they would need to get from other plant foods or supplements. With animal protein, however, Vitamin D3 appears to be low and unless some seafood is included in the diet, no long-chain omega-3 fatty acids will be obtained.
Consider What Foods to Eat to Get All The Nutrients You Need
It is important to learn some basic nutrition so that you can find the right foods with the right nutrients to include in your diet . This information would even give you the edge over non-vegans. Most people don’t look at their diet as a whole and determine if they consumed enough of each critical nutrient from their regular foods. Even non-vegans take multivitamins, but hopefully this guide will allow you to pinpoint specific nutrients to look out for when choosing ingredients for your meals as well as vitamin supplementation.
My recommendation to a vegan would be to supplement with vitamin B12, vitamin D3, iodine and Omega 3 long chain fatty acid (EPA and DHA) daily, and then find enough plant-based sources of all the other nutrients. Find the plant-based sources you enjoy the most and try to include them as much as possible in your diet.