Antioxidants are powerful compounds that are found in a variety of foods. Some antioxidants are essential nutrients whereas others are not. Antioxidants have been found to play a major role in health and disease.
- What are Antioxidants?
- What Antioxidants Do in the Body
- Daily Intake Recommendations for Antioxidants
- How to Consume Enough Antioxidants as a Vegan
- Vegan Food Sources of Antioxidants
- Antioxidant Supplements
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What are Antioxidants?
There are many types of antioxidants found in different foods. The two most common antioxidants are essential nutrients – vitamin C and vitamin E. 1
Vitamin C is the major water soluble antioxidant and is in most fruits and vegetables 1. Beta-carotene is also a common water soluble antioxidant, however it is not technically an essential nutrient 1. Water soluble means that the antioxidant works in the watery areas of the body (as opposed to fatty areas).
Vitamin E is the major fat soluble antioxidant and can be found in fatty foods such as avocado, nuts and seeds, vegetable oils and leafy green vegetables 1. Fat soluble means it works in the fatty areas of the body. Fatty areas includes subcutaneous fat (fat under the skin that we can “see”) and also cell membranes, the brain and other tissues that contain fat.
Selenium and manganese are two additional essential nutrients that play a role in how antioxidants work 1.
There are many antioxidants that are not essential nutrients including:
These are general categories of antioxidant compounds but there are many more specific compounds. For example, curcuminoids found in turmeric are a type of polyphenol.
What Antioxidants Do in the Body
Antioxidant is a common word in the nutrition world, but explaining them requires some understanding of chemistry.
There are compounds in the body called free radicals which can cause damage if levels become too high 1. Bodies have mechanisms to maintain a good balance of free radicals but stresses on the body can result in increased levels of free radicals 1.
The body fights free radicals by using antioxidants that it produces on its own, and those that come from food 1. Antioxidants work by neutralizing free radicals, so the free radicals can no longer cause damage to cells or DNA 1.
The body is essentially comprised of watery areas and fatty areas, and damaging free radicals can be found in both. Therefore, we need antioxidants to work in both the watery and fatty areas to fight free radicals.
Daily Intake Recommendations for Antioxidants
As you can see, there are many unique antioxidant compounds. Apart from the few antioxidants that are essential nutrients, there are no set intake levels for antioxidants 2.
Recommended intakes for vitamin C are: 2
- 90 mg per day for adult men (over age 19)
- 75 mg per day for adult women (over age 19)
For both men and women over 19 years, the upper limit of vitamin C is 2000 mg per day 2. This means consistently consuming vitamin C up to or over this amount could result in harm. Always speak to your doctor before starting any supplements because more is not always better.
Recommended intakes for vitamin E are: 2
- 15 mg per day for both men and women over age 19
The upper limit for vitamin E is 1000 mg per day for both men and women over age 19 2. The upper limit for vitamin E is specifically for intake from supplements and fortified foods combined (not from vitamin E naturally occurring in foods). Again, always speak to a doctor before starting supplements as there are many harms that could result.
How to Consume Enough Antioxidants as a Vegan
Antioxidant compounds are found in many foods; however plant-based foods generally contain higher levels of antioxidants compared to animal-based foods 3. So if plant-based foods contain higher levels of antioxidants (on average) compared to animal foods, someone following a vegan diet should be getting lots of antioxidants right?
There are many ways to consume a vegan diet and some vegans may not be eating an abundance of whole plant foods. If this sounds familiar, antioxidant intake could be low. Since antioxidants are not an essential nutrient, overall nutrient needs may be met and antioxidant intake could be overlooked. However, there are many reported health benefits to consuming more antioxidants, therefore a focus on consuming more may be beneficial.
While most plant-based foods contain some level of antioxidants, there are certain foods that have higher levels 3. As a very general rule, the more pigmented a food is, the more likely it is to have a higher concentration of antioxidants.
For example, red onions would contain more antioxidant compounds compared to white onions. Leafy greens that are darker in color like spinach would have more antioxidants compared to a lighter leafy green such as iceberg lettuce. So, one way to increase antioxidant intake is to focus on selecting foods that are brighter in color or more pigmented.
Additionally, there are many beverages and “other” foods that contain high levels of antioxidants 3. Coffee, espresso, tea leaves, tea leaf powders and dark chocolate can all provide additional antioxidants 3. Tomato-based sauce, basil pesto, sundried tomatoes and mustard paste are a few “other” foods that fared well in terms of antioxidant capacity 3.
This again emphasizes the benefits of including a wide variety of foods in the diet. The more of these high-antioxidant ingredients used, the better your total antioxidant status can be. It’s also important to realize that antioxidants are just one component of food. Even foods low in antioxidants can still be perfectly healthy for other reasons and great to include in the diet.
Vegan Food Sources of Antioxidants
The highest concentration of antioxidants in any food (excluding supplements and herbal medicines) is found in plant-based foods, specifically certain herbs and spices 3. While this is a fantastic benefit of including herbs and spices in your diet, it’s also important to keep in mind that people tend to use small quantities of these ingredients in cooking. So even though there may be high levels of antioxidant compounds, the total amount you may get could still be low.
The antioxidant content of different foods, even within the same food group, is highly variable 3. One study quantified the amount of antioxidants in over 3000 food samples from around the world. They grouped foods into different categories and reported the average antioxidant concentration of these food groups 3.
Overall, plant-based food groups (spices and herbs, berries, chocolate, nuts and seeds, fruit, vegetables) had the highest average antioxidant concentrations 3. Animal-based foods consistently had the lowest antioxidant concentrations with eggs being the lowest followed by fish and seafood, dairy products, poultry and meat all coming in at the bottom of the list 3.
While the health benefits of a food aren’t solely related to the antioxidant content, the more antioxidants consumed from food, the better your long-term healthy may be.
Limitations with Reporting Average Antioxidant Concentrations
Keep in mind that the averages for certain food groups can easily be skewed by one or two foods with a very high or low concentration of antioxidants.
For example, chocolates and sweets was one category of foods high on the list for having the most antioxidants 3. However it was the high percentage dark chocolates (70-99% cocoa) that resulted in this being one of the top categories and not the white chocolate or milk chocolate products with less than 30% cocoa 3.
Also, some of the highest antioxidant food items were dried 3. Without water to dilute the antioxidants, it makes sense that dried foods (ex. dried herbs and spices, dried fruit) would be more concentrated in antioxidants. Again, this doesn’t necessarily mean these foods are superior to their non-dried counterparts. A fresh apple is a great choice; even though dried apples are more concentrated in antioxidants, it’s just due to the lack of water content.
Antioxidant supplements are everywhere. For the health-conscious vegan, it may be tempting to increase antioxidant intake by supplementing. However, antioxidant supplements are unhelpful at best and harmful at worst 1, 4, 5, 6, 7. Always speak to a doctor before starting any supplements.
As with most things, whole foods are far superior to any supplement. There are many reasons for this including:
- Supplements contain only a few select antioxidants compared to whole foods which contain a wide range of antioxidants along with other nutrients. While we know the effect of certain compounds, many more are not identified yet, but could still be beneficial. These other compounds may be in whole foods but not supplements.
- Supplements are highly concentrated and more is not always better. Especially with certain medical conditions, highly-concentrated supplements could be dangerous. Always speak with your doctor before starting any new supplement or herbal product.
It’s always best to meet nutrient needs through foods first. If you’re concerned about not meeting nutrient needs through food, speak with a dietitian.
Summary: Antioxidants for Vegans
Antioxidant compounds have a huge potential to benefit human health by protecting cells from free radical compounds which can be damaging.
There are many antioxidant compounds, and different compounds can be found in a variety of foods. Plant-based foods typically contain higher concentrations of antioxidants compared to animal-based foods. Each category of food contains varying levels of antioxidant concentration, therefore consuming a wide variety is important.
Antioxidant supplements are usually not found to be helpful and may be harmful. Do not start taking any supplements without first speaking to your doctor.
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- Antioxidants and Cancer Prevention
- Dietary Reference Intakes Tables
- The total antioxidant content of more than 3100 foods, beverages, spices, herbs and supplements used worldwide
- Antioxidants: In Depth
- Dietary antioxidants and human cancer
- A review of the epidemiological evidence for the 'antioxidant hypothesis'
- Oxidative Stress and the Use of Antioxidants in Stroke
This is a curated list of references for the topics above and is not intended to be comprehensive.
Disclaimer: always speak with a doctor before changing your diet. Please read our full website disclaimer.
Author Profile: Nicole Stevens
Nicole is a vegan Registered Dietitian (RD) and founder of Lettuce Veg Out. She provides vegans with balanced meals and easy-to-understand nutrition science.
Having attained a Masters degree and passing a national registration exam, Nicole is a trusted source of nutrition information. She uses this knowledge to educate others about vegan diets and how to thrive as a vegan.