Vitamin B2: A Practical Guide

Riboflavin (Vitamin B2) enables your body to break down proteins, fats, and carbohydrates and plays a vital role in maintaining your body’s energy supply.  

Riboflavin helps convert carbohydrates into adenosine triphosphate (ATP) for use in your cells.  

You require almost twice as much riboflavin to burn fat compared to when you burn glucose for fuel.

Riboflavin also plays an essential role in producing red blood cells and releasing energy from your food, as well as maintaining the health of your skin and digestive tract.  

You will require more vitamin B2 if you are losing weight or active, and even more if you are both losing weight and active at the same time.

Vitamin B2 deficiency symptoms

Symptoms of riboflavin deficiency include:

Satiety response and fat loss

Our satiety analysis of people using the Nutrient Optimiser shows a strong satiety response to food that contains more vitamin B2.  People who consume foods that contain more vitamin B2 tend to eat about 25% fewer calories.  

But more vitamin B2 is not necessarily better.   Consuming more than about 8 mg per 2000 calories of vitamin B2 doesn’t appear to offer any additional benefit (at least in terms of satiety).  The rebound satiety effect we see in the chart above seems to due to people taking higher doses of supplemental vitamin B2. A processed diet with vitamin B2 supplements does not provide the same satiety effect as consuming whole foods that contain more thiamine.  Isolated supplements never seem to provide the same benefit as nutrient-dense whole food.

Riboflavin optimal target levels

The average vitamin B2 intake of Optimisers is 5 mg per 2000 calories with an 85th percentile intake of 8 mg per 2000 calories.  This is significantly higher than the Estimated Average Requirement of 1.1 mg/day and the Daily Recommended Intake of 1.3 mg/day.  

Based on the satiety response to B2, we suggest a stretch target for riboflavin of 6.0 mg/day for men and 4.8 g/day for women.    

nutrient averageEAR RDIstretch (men)stretch (women)
riboflavin (B2) (mg)

Vitamin B2 upper limit and side effects

It’s hard to overdose on vitamin B2 because it is water-soluble and easily excreted in the urine.   

Popular vitamin B2 rich foods

Popular food sources of vitamin B2 include:

  • liver,
  • egg white,
  • asparagus,  
  • zucchini,
  • milk,
  • broccoli,  
  • whole egg,
  • parsley,
  • kale,  
  • cauliflower, 
  • cucumber, and 
  • cottage cheese.  

Availability of Vitamin B2 in the diet

Riboflavin availability has increased with the fortification of grains and cereals since the 1940s. As shown in the chart below (data from USDA Economic Research Service), fortification provides enough B2 to meet the Daily Recommended Intake (i.e. 1.3 mg/day), but not the optimal amounts that align with greater satiety and that reduces your cravings.  

It’s worth noting that milk from cows fed on fresh grass has more riboflavin than from cows fed with dried grass, which leads to natural annual fluctuations in riboflavin.  

Vegans may need to pay extra attention to the vitamin B2 intake

Without eggs, milk, liver, or a lot of fresh vegetables in their diet, vegans may struggle to get enough vitamin B2.  People who do not consume animal products should take care to minimise processed foods which contain minimal vitamin B2 and focus on nutrient-dense minimally processed whole foods.  

People following a high-fat diet (e.g. keto or low carb) may also need to prioritise riboflavin given that high-fat foods typically don’t contain a lot of riboflavin.  As noted above, you also need more vitamin B2 to convert the fat in your diet to usable energy in your cells.  

Fun fact about B2 supplements

It’s the vitamin B2 that causes the fluorescent pee when we supplement B vitamins, so vitamin manufacturers often like to add a little bit extra to make you feel you are getting your money’s worth.  

However, our analysis indicates that there you won’t be getting any additional benefit beyond around 8 mg/day of vitamin B2.  Isolated supplements alone are unlikely to provide significant benefit. You should prioritise food first before investing in supplementation.  

Storage losses 

Riboflavin is heat stable, so it doesn’t break down when you cook it.  However, vitamin B2 does leach into the cooking water and degrades quickly when exposed to light (this is why milk cartons are opaque).

Processing losses 

Between ten and twenty per cent of riboflavin is lost in the pasteurisation of milk and 10 to 20% in the cooking of meat.

Nutrient profile 

The nutrient fingerprint below shows the availability of nutrients in the foods that contain the most riboflavin.   Riboflavin is relatively easy to obtain from nutrient-dense foods and meals.

Nutrient Optimiser

If you ensure you’re getting enough Vitamin B2 (along with ALL the other essential nutrients), we’d love you to check out Nutrient Optimiser.  We have designed Nutrient Optimiser to be the quickest and easiest way to optimise your nutrition at the micronutrient level.  

You can select from our database of five hundred recipes to plan your meals for the coming week to ensure you will get the nutrients you need to thrive. 

Then, if you are able to track your current diet for a few days, Nutrient Optimiser will identify the foods and meals that you need to fill your macro and micronutrient gaps. 

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