Vitamin B2 or riboflavin is one of the water-soluble B-complex vitamins critical to our well-being. It performs several functions in the body—it promotes eye health and the metabolism of carbs and proteins. It also protects us from a wide range of diseases and can be used as treatment or part of treatment for several health conditions.
In this article, you’ll learn how riboflavin works and which are the essential vitamin B2 foods. The following paragraphs will also shed light on recommended daily dosage and deficiency-related information. Let’s get right into it.
Discovery of Vitamin B2
Unlike other vitamins discovered due to diseases arising from nutritional deficiencies, vitamin B2 was uncovered out of the sheer curiosity of scientists studying vitamins at the time. After discovering water-soluble thiamine, researchers realized there were several additional water-soluble factors they named the vitamin B2 complex. However, they still hadn’t discovered riboflavin function at this point.
They started analyzing different foods during the 1900s, including milk, yeast, liver, and whole wheat, to identify the above-mentioned additional water-soluble factors. As there weren’t any known classical nutritional diseases attributable to riboflavin deficiency, the growth-stimulating properties of vitamin B2 rich foods on rats helped the researchers identify and eventually extract vitamin B2.
Riboflavin was finally discovered in 1922 by Richard Kuhn in Germany and Theodor Wagner-Jauregg in Austria. Richard Kuhn and Paul György later isolated the compound in 1933. However, it wasn’t until 1939 that vitamin B2 benefits and nutritional usefulness for man were fully uncovered.
Let’s go through the essential riboflavin functions together in the following section.
Vitamin B2 Functions
Vitamin B2 is essential for a healthy life. Besides causing various health issues, riboflavin deficiency can affect the functionality of some other B-complex vitamins in your body (B1, B3, and B6) and lead to other health complications.
Furthermore, riboflavin promotes the breakdown of carbs, proteins, and fats, producing energy to power our daily activities. Namely, vitamin B2 is in charge of ATP molecules production from nutrients obtained from food. These molecules are energy sources that fuel our bodies and enable proper functioning.
In addition to the riboflavin benefits mentioned above, here are some additional vitamin B2 functions:
- It protects and maintains the mucous membrane necessary for nutrient absorption in the gut system.
- It promotes liver health.
- It protects eyes, muscles, nerves, and skin from diseases that arise due to riboflavin deficiency.
- It helps with the absorption of nutrients and minerals.
- It aids adrenal glands’ hormone production.
- It’s linked to improved development of infants in terms of length and weight.
Some of the Best Riboflavin Foods
This section contains a detailed overview of some of the best food sources of this essential vitamin.
Beef liver contains 2.755–3.425 mg of vitamin B2 per 100 g, making it the best source of riboflavin. Raw beef liver provides the lowest amount of riboflavin (2.755 mg per 100 g). Furthermore, a typical beef liver serving weighing 589 g contains 16.23 mg of riboflavin. In other words, you get 2.04 mg riboflavin per 100 calories of raw beef liver.
On the other hand, pan-fried or braised beef liver offers the highest amount of riboflavin (a whopping 3.425 mg per 100 g).
Eggs are also some of the top foods with riboflavin, containing 0.376–1.977 mg of riboflavin per 100 g. Dried whole eggs offer the highest riboflavin levels (1.977 mg per 100 g). That is, there’s 0.17 g of riboflavin per 100 calories of dried whole eggs. On the other hand, scrambled eggs offer the lowest amount of vitamin B2 (0.376 mg per 100 g).
Another decent riboflavin food source is apple, offering 0.011–0.028 mg of riboflavin per 100 g. A raw unpeeled apple has a riboflavin content of 0.026 mg per 100 g. One cup (125 g) of chopped raw apples provides 0.03mg of riboflavin. That’s 0.05 mg of vitamin B2 per 100 calories.
You can get the highest amount of riboflavin from raw peeled apples (0.028 mg per 100 g). Boiled peeled apple, on the other hand, offers only 0.012 mg of riboflavin per 100 g.
The amount of riboflavin in this vitamin B2 source ranges between 0.053 and 0.143 mg per 100 g. While raw Florida avocados provide the least riboflavin (0.053 mg per 100 g), uncooked California avocados offer the highest levels (0.143 mg per 100 g).
One cup of pureed Florida avocados offers 0.12 mg of vitamin B2. That is, 100 calories of the pureed Florida avocados contain 0.04 mg of riboflavin.
Another vitamin B2 source worth mentioning is spinach, offering 0.106–0.263 mg of riboflavin per 100 g. Raw spinach provides 0.189 mg of vitamin B2 per 100 g.
One cup (30 g) of raw spinach corresponds to 0.06 mg of riboflavin. Moreover, 100 calories of raw spinach contain 0.82 mg of the B2 vitamin, making spinach one of the relatively rich riboflavin food sources.
Spinach souffle contains the highest amount of riboflavin (0.263 mg per 100 g), followed by boiled and frozen spinach, offering 0.236 and 0.224 mg of vitamin B2 per 100 g, respectively. Canned spinach provides the least amount of riboflavin (0.106 mg per 100 g).
Kidney beans rank relatively high among the vitamin B2 foods and contain 0.015–0.25 mg of riboflavin per 100 g. Raw mature red kidney beans yield 0.215 mg of the B2 vitamin per 100 g. One cup (184 g) of uncooked red kidney beans provides 0.4 mg of riboflavin. That is, 100 calories of raw red mature kidney beans get you 0.06 mg of vitamin B2.
While raw sprouted kidney beans offer the most riboflavin (0.25 mg per 100 g), canned kidney beans provide only 0.015 mg per 100 g.
Asparagus, another of the good vitamin B2 food sources, provides 0.032–0.141 mg of riboflavin per 100 g. Raw asparagus offers 0.141 mg of riboflavin per 100 g. On the other hand, the canned cream of asparagus soup prepared with water contains the lowest riboflavin levels (0.032 mg per 100 g).
Furthermore, one cup (134 g) of raw asparagus offers 0.19 mg of vitamin B2. In other words, there’s 0.71 mg of this vitamin per 100 calories.
Tomatoes also rank high among the best riboflavin foods, offering 0.019–0.489 mg of riboflavin per 100 g. Sun-dried tomatoes yield a mouthwatering 0.489 mg of the B2 vitamin per 100, while raw tomatoes provide the least amount (0.019 mg per 100 g).
A typical one-cup serving (54 g) of sun-dried tomatoes offers 0.26 mg of riboflavin. This means that 100 calories of sun-dried tomatoes amount to 0.19 mg of riboflavin.
Oats are among the top foods high in riboflavin and contain 0.016–2.05 mg of vitamin B2 per 100 g. Regular instant oats provide the lowest riboflavin levels at 0.016 mg per 100 g.
Consuming ready-to-eat cereals is one of the easiest ways to get vitamin B2 from oats. However, not all oat cereals offer the same amount of riboflavin—the levels can significantly vary among brands.
For example, Quaker Quick Oats offer a meager 0.12 mg of the B2 vitamin per 100 g. In other words, a half-a-cup cup serving (40 g) of Quaker Quick Oats yields only 0.05 mg riboflavin. On the other hand, Kellogg’s Special K Multigrain Oats & Honey is a highly riboflavin-rich food, offering the most vitamin B2 (2.05 mg per 100 g).
Quinoa also belongs to the category of foods high in vitamin B2. This grain’s riboflavin content ranges between 0.11 and 0.318 mg per 100 g. Cooked quinoa offers the least amount of riboflavin (0.11 mg per 100 g). Namely, a typical serving of one cup (185 g) of cooked quinoa yields 0.2 mg of riboflavin. In other words, you get 0.09 mg of vitamin B2 per 100 calories.
On the other hand, uncooked quinoa offers the highest riboflavin levels (0.318 mg per 100 g).
Almonds can also be an excellent vitamin B2 food source. The riboflavin content of almonds varies between 0.148 and 1.328 mg per 100 g. Raw almonds offer a staggering 1.014 mg of vitamin B2 per 100 g, and a one-cup serving (95 g) yields 0.96 mg of riboflavin. In other words, you can get 0.18 mg of vitamin B2 per 100 calories of almonds.
Dry-roasted and honey-roasted almonds closely follow raw almonds with slightly lower riboflavin content—0.967 and 0.953, respectively.
You can also get vitamin B2 from almond-containing ready-to-eat foods high in riboflavin. For example, Post Honey Bunches of Oats with Almonds offer the highest riboflavin levels (1.328 mg per 100 g). On the other hand, Quaker Sun Country Granola with Almonds provides only 0.18 mg of riboflavin per 100 g.
Whole Wheat Bread
Whole wheat bread’s riboflavin content ranges from 0.08 to 0.284 mg per 100 g. Whole wheat pita bread provides the lowest vitamin B2 levels (0.08 mg per 100 g). One large whole wheat pita bread (64 g) will get you as little as 0.05 mg riboflavin. In other words, consuming 100 calories of whole wheat pita bread will provide you with 0.38 mg of vitamin B2, making it a modest vitamin B2 food source.
However, toasted whole-wheat bread can provide you with much more riboflavin. Namely, this toasted good provides the highest vitamin B2 levels in the whole wheat bread category (0.284 mg per 100 g).
Bagel’s riboflavin content sits between 0.052 and 0.338 mg per 100 g. Egg bagel contains 0.235 mg of vitamin B2 per 100 g, therefore a typical 1 oz egg bagel serving (28.35 g) offers 0.07 mg of riboflavin. In other words, you can get 0.08 mg of riboflavin per 100 calories.
Oat bran bagel is the best riboflavin food source in the bagel category as it contains the most riboflavin content (0.338 per 100 g). On the other hand, plain, unenriched bagels offer the least vitamin B2 (0.052 mg per 100 g).
Chicken meat and thighs are also foods that contain riboflavin, offering 0.032–0.255 mg of vitamin B2 per 100 g. Raw chicken drumsticks and thighs with skin provide the lowest amount of vitamin B2 per 100 g (0.032 mg). A 1 oz serving (28.35 mg) delivers 0.01 mg of vitamin B2. Simply put, 100 calories of raw chicken provide 0.01 mg of riboflavin.
On the other hand, thermally processed broilers’ (6–10 weeks old chicken) or fryers’ (7–10 weeks old chicken) meat offers the highest riboflavin levels. Namely, vitamin B2 levels in fried broiler or fryer thighs without skin reach 0.255 mg per 100 g.
Salmon is also one of the good sources of vitamin B2, offering 0.101–0.543 mg of riboflavin per 100 g. Atlantic salmon cooked with dry heat provides 0.135 mg of vitamin B2 per 100 g. A typical serving of half a 0.5 fillet (178 g) will get you 0.24 mg riboflavin content. This means you can get 0.07 mg of vitamin B2 per 100 calories.
The smoked Alaskan red sockeye salmon fillets with skin offer the highest amount of riboflavin (0.543 mg per 100 g), making it excellent vitamin B2 food in the fish category. On the other hand, smoked chinook salmon and the lox style smoked chinook salmon provide the least vitamin B2 amounts (0.101 mg per 100 g).
Cod can also be found among noteworthy vitamin B2 sources, as it offers 0.045–0.24 mg of riboflavin per 100 g. Raw Pacific cod provides the lowest vitamin B2 content (0.045 mg per 100 g). A typical one-fillet serving (116 g) provides 0.05 mg of riboflavin, which means that 100 calories (1.45 g of raw Pacific cod) amounts to 0.07 mg of vitamin B2.
On the other hand, dried and salted Atlantic cod yields the most riboflavin per 100 g (0.24 mg).
Trout also classifies as food high in riboflavin. Riboflavin content in this fish species varies between 0.09 and 0.423 mg per 100 g. For example, raw wild rainbow trout offers 0.105 mg vitamin B2 per 100 g. A single raw wild rainbow trout fillet (159 g) contains 0.17 mg of the B2 vitamin. This means there’s 0.09 mg of riboflavin in 100 calories.
Raw rainbow trout provides the lowest vitamin B2 content (0.09 mg per 100 g). On the other hand, trout cooked with dry heat is one of the most riboflavin-rich foods in this category, offering 0.423 mg of vitamin B2 per 100 g.
Vitamin B2 content of whole milk varies between 0.162 and 1.205 mg per 100 g. For example, whole buttermilk contains 0.172 mg of riboflavin per 100 g. A one-cup serving (245 g) of whole buttermilk yields 0.42 mg of vitamin B2. In other words, there’s 0.28 g of riboflavin in 100 calories of whole buttermilk.
Dry whole milk with added vitamin D qualifies as an excellent vitamin B2 food source, offering the highest riboflavin amount (1.205 mg per 100 g). In contrast, whole chocolate milk with added vitamins A and D provides the lowest amount (0.162 mg per 100 g).
Skim milk contains 0.14–0.194 mg of riboflavin per 100 g. Namely, calcium-fortified skim milk contains the lowest amount of riboflavin (0.14 mg per 100 g). One cup (247 g) of milk contains 0.35 mg of vitamin B2. Simply put, you can get 0.4 mg of riboflavin per 100 calories of milk.
In contrast, protein-fortified skim milk with vitamins A and D is one of the best vitamin B2 foods in this category, containing the highest riboflavin content (0.194 mg per 100 g).
Mushrooms offer 0.021–1.27 mg of riboflavin per 100 g. For example, raw enoki mushrooms provide about 0.2 mg of riboflavin per 100 g. One large raw enoki mushroom (5 g serving) offers only 0.01 mg of vitamin B2 vitamin. In other words, you can get 0.54 mg of riboflavin per 100 calories.
Dried shiitake mushroom is a highly riboflavin-rich food, providing the highest riboflavin amount among mushrooms (1.27 mg per 100 g). In other words, only 100 g of these mushrooms provides you with a whopping 98% DV of vitamin B2. Canned mushrooms, on the other hand, offer the lowest riboflavin levels (0.021 mg per 100 g).
Consuming other mushrooms like raw crimini, grilled portobello, and raw oyster mushrooms can give you 0.49, 0.403, and 0.349 mg of riboflavin 100 g, respectively.
Riboflavin in food like oysters ranges from 0.055 to 0.433 mg per 100 g. Raw Pacific oyster yields 0.233 mg of vitamin B2 per 100 g. One medium raw oyster (50 g) contains 0.12 mg of vitamin B2. Simply put, 100 calories of raw Pacific oyster amounts to 0.29 mg riboflavin.
Pacific oyster cooked with moist heat (boiling, steaming, poaching, etc.) is a great vitamin B2 source, containing the highest riboflavin levels (0.433 mg per 100 g). In contrast, eastern oysters cooked with dry heat contain the lowest amount of vitamin B2 (0.055 mg per 100 g).
Finally, one cup (162 g) of canned eastern oysters contains 0.27 mg of riboflavin per 100 g.
canned eastern oysters offer a 35% DV of riboflavin per can (12 oz).
Tempeh provides 0.358 mg of riboflavin per 100 g. One cup (166 g) of tempeh offers 0.59 mg of vitamin B2. This means you can get 0.19 mg of riboflavin from consuming 100 calories of tempeh. A 100 g serving of tempeh provides a 28% DV for vitamin B2 per 100 g, making it an excellent riboflavin food to include in your diet.
The riboflavin content of mackerel ranges between 0.17 and 0.58 mg per 100 g. Salted mackerel offers only 0.19 mg of vitamin B2 per 100 g. Furthermore, you can get 0.26 mg of riboflavin from a one-cup serving (136 g) of salted mackerel. In other words, consuming 100 calories of salted mackerel provides you with 0.06 mg of vitamin B2.
King mackerel cooked with dry heat is one of the most riboflavin-rich foods. It offers the highest riboflavin levels among mackerels (0.58 mg per 100 g). On the contrary, raw Spanish mackerel yields the lowest vitamin B2 amount (0.17 mg per 100 g).
Benefits of Vitamin B2 Supplementation
Taking vitamin B2 can function preventatively against various conditions. Scientific evidence suggests it’s somewhat effective in treating headaches, particular eye-related issues, and even some types of cancer.
For example, studies show that you could use vitamin B2 for migraine management. Namely, consuming high doses of riboflavin (400 mg a day) is likely to reduce the frequency of migraine attacks. However, riboflavin doesn’t affect the pain intensity or the duration of migraines.
Riboflavin also helps prevent cataracts. What’s more, studies show that people with regular adequate riboflavin intake face a lower risk of developing this condition.
Taking riboflavin can also help reduce the level of homocysteine in the blood by 40% within 12 weeks. Homocysteine is a sole risk factor for developing severe health conditions such as glaucoma, vascular disease, and schizophrenia.
Additionally, recent studies uncovered more potential vitamin B2 benefits for health, but further research is required to verify them. For example, there are indications, but still not enough evidence, that riboflavin might be effective against lactic acidosis in people with AIDS. Researchers are also currently looking into its potential to decrease the risk of cervical cancer, esophageal cancer, liver cancer (in individuals under 55 when taken alongside niacin), multiple sclerosis, etc.
Besides the aforementioned benefits, there are also suggestions that riboflavin may positively affect acne, aging. Furthermore, it can help boost the immune system and reduce canker sores, alongside many other health problems.
It’s also possible that more vitamin B2 benefits will be discovered as research continues.
Adequate Riboflavin Dosage
Recommended daily dose of vitamin B2 depends on your age, reproductive status, and gender. The RDA is 1.3 mg for men and 1.1 mg for women above 19 years. However, the amount can be increased to help with treating specific diseases.
Riboflavin is safe for pregnant and breastfeeding women when following the vitamin B2 dose—1.4 mg per day during pregnancy and 1.6 mg daily during breastfeeding.
Infants and children should adhere to the following daily riboflavin dosage:
- Infants (0–6 months): 0.3 mg
- Infants (6–12 months): 0.4 mg
- Toddlers (1–3 years): 0.5 mg
- Children (4–8 years): 0.6 mg
- Children (9–13 years): 0.9 mg
- Males (14–18 years): 1.3 mg
- Females (14–18 years): 1.0 mg
Vitamin B2 is generally considered safe, even when taken in higher doses than recommended. This is because the body uses most riboflavin immediately, and the excess is excreted from the body through urine. What’s more, your body can only absorb up to 27 mg of vitamin B2 at a time.
When taken in larger doses for a short time, riboflavin is unlikely to cause serious health problems. Some studies prove that even doses as high as 15 mg of riboflavin are safe when taken once every two weeks for ten weeks.
However, adhering to the recommended vitamin B2 dose is desirable. Namely, excessive amounts of riboflavin can change the color of urine of particular individuals to bright yellow or cause diarrhea.
Vitamin B2 Deficiency
Cases of riboflavin deficiency are rare in developed countries like the US due to high living standards and the availability of vitamin B2 in foods. However, despite good living standards and access to vitamin-rich foods, deficiency may occur in people with digestion issues and underweight individuals following extreme diets.
Alcoholics, teens, and geriatrics are also at risk of vitamin B2 deficiency due to malnutrition. Additionally, people with medical conditions like hepatitis, biliary obstruction, and cirrhosis can have decreased riboflavin absorption.
The lack of vitamin B2 can cause a wide range of health problems including, anemia, sore throat, mouth and lip sores, swelling of mouth tissues, and skin inflammation. Symptoms can occur within days of becoming deficient.
Supplements are a good source of riboflavin for those who cannot get adequate amounts of this vitamin from food due to restricted access to riboflavin foods or particular health problems. Vitamin B2 can be found in B-complex vitamins and multivitamins but is also available separately in 25 mg, 50 mg, and 100 mg doses. There are also higher doses, like vitamin B2 400 mg, mainly used for managing migraines.
Vitamin B2 Deficiency Diseases
Despite being rare, especially in developed countries, riboflavin deficiency can pose serious health risks. Namely, ariboflavinosis (deficiency in this vitamin) can cause various skin disorders, hyperemia, and mouth and throat edema.
Furthermore, vitamin B2 deficiency symptoms can also cause swollen or cracked lips, hair loss, itchy and red eyes, and weakening of the liver and nervous system. Some experience reproductive problems or a sore throat. Since hair loss is one of the symptoms, many resort to supplements due to vitamin B2 benefits for hair.
Other nutrient deficiencies often accompany ariboflavinosis, as serious vitamin B2 deficiency often impairs the metabolism of other nutrients. For example, the metabolism of other B vitamins is decreased due to the reduced levels of flavin coenzymes.
Health conditions like cataracts and anemia develop as a result of prolonged or severe B2 vitamin deficiency. The effects of less severe shortages can quickly be reversed by supplementation. However, when deficiency develops into more complex problems like cataracts, supplements rarely can address the issue.
The following paragraphs list groups that are more susceptible to ariboflavinosis.
Your vulnerability to riboflavin deficiency depends on your reproductive condition, lifestyle, health condition, and diet. These are the groups most susceptible to developing a deficiency in this essential nutrient:
Pregnant and Lactating Mothers and Their Infants
Riboflavin is crucial for pregnancy and breastfeeding, as that’s the period of high demand for this nutrient. Pregnant and lactating mothers who rarely consume dairy products or foods high in vitamin B2 are at even greater risk of developing vitamin B2 deficiency.
This problem of riboflavin deficiency is common in both developing and developed countries and among vegetarian women in developed countries. Insufficient riboflavin during pregnancy can lead to preeclampsia.
Luckily, supplementation and an adequate diet can reduce the risk of preeclampsia, ensure a high concentration of riboflavin in breast milk, and improve infant birth weight and length.
This group is also at risk of vitamin B2 deficiency due to the stress exercise produces in the metabolic pathways that utilize riboflavin. For this reason, athletes require more riboflavin than ordinary people.
Another reason why they’re more likely to develop this deficiency is that some vegetarian athletes exclude almost all animal products from their diet, an important source of riboflavin. For this reason, vegetarian athletes are recommended to consult a dietician who could help them avoid deficiency despite dietary restrictions.
Vegans and People Who Don’t Consume Dairy Products
The main reason for these groups being at risk of riboflavin deficiency is that they don’t consume milk—a substantial riboflavin source. Vegans face an even greater danger of lacking vitamin B2, as they exclude more essential vitamin B2 food sources coming from animals such as meat and eggs.
Riboflavin Transporter Deficiency Patients
This condition, linked to various health issues such as hearing loss, bulbar palsy, respiratory difficulty, etc., can develop early in life. What characterizes it, besides the previously mentioned conditions, is riboflavin transporter deficiency. In other words, this disorder can cause a decreased absorption of vitamin B2, putting this group at greater risk of ariboflavinosis.
Unfortunately, there’s no cure for this disease yet, but high-dose vitamin B2 supplementation can help alleviate some of the symptoms.
Riboflavin is a vitamin deserving our attention for being highly critical for our body health. As already mentioned, B2 vitamin deficiency may lead to devastating consequences. Therefore, it’s essential to maintain optimal levels of vitamin B2.
The best way of getting adequate amounts of this vitamin is through a well-balanced diet and, if necessary, riboflavin tablets or other forms of vitamin B2 supplements. Hopefully, this article managed to inform you about all you need to know about the most important vitamin B2 foods sources you can employ to keep this type of nutritional deficiency at bay.
What does vitamin B2 do?
Vitamin B2 is beneficial for the body in numerous ways. It’s involved in hormone production, nutrient breakdown and absorption, and improved functionality of our organs and systems. It also helps maintain eyes and skin health while preventing a wide range of diseases like cataracts, migraine headaches, and liver disease.
What is the best source of vitamin B2?
Both supplements and foods rich in riboflavin are excellent sources of vitamin B2. Lamb liver stands out among food sources, providing up to 279% DV of riboflavin per 100 g serving.
What causes vitamin B2 deficiency?
Several factors lead to vitamin B2 deficiency, malnutrition being the main trigger. People who don’t consume foods rich in riboflavin, such as milk and eggs, are at higher risk of a deficiency. Additionally, people with health conditions that interfere with nutrient absorption (e.g., riboflavin transporter deficiency sufferers) can develop vitamin B2 deficiency. Lastly, vegans and vegetarian athletes are also at a high risk of riboflavin deficiency due to diet restrictions.
What does a riboflavin deficiency cause?
Riboflavin deficiency can affect the proper function of organs like the liver. It can also undermine the absorption of other B-complex vitamins. Vitamin B2 deficiency has been linked to health complications such as anemia, sore throat, mouth and lip sores, swelling of mouth tissues, skin inflammation, etc.
Is too much vitamin B2 bad for you?
There’s no recorded evidence of health problems arising from taking too much riboflavin, but there are strong indications that excessive riboflavin consumption can change urine color and cause diarrhea in some individuals. Therefore, it’s essential to adhere to the correct dosage when consuming vitamin B2 foods and supplements, especially during pregnancy.