The Amazing Benefits of the Mysterious Vitamin P

In the first part of the 20th century, vitamin P was known to reduce blood sugar and improve insulin resistance. What is it? It’s now known as flavonoids and you need to eat them.

You may not know that in the first part of the twentieth century there was such a thing as vitamin P. Not only that, but vitamin P helped to reduce blood sugar, improve insulin resistance, reduce lipids, and fight inflammation. It sounds like pretty good stuff, and you can’t help but wonder where it went. Actually, vitamin P is a substance we now call flavonoids. And yes, flavonoids have been credited with all of those effects and possibly more.

A flavonoid is a byproduct of plant metabolism, so you get flavonoids when you eat plants. Hesperidin is a popular and healthy type of flavonoid that comes from citrus fruits. In a recent study by the Journal of Strength of Conditioning, researchers wanted to see if hesperidin supplementation would benefit chemical and stress indicators during exercise.

In this case researchers looked at rats, not people, but the results were telling. They had the rats do different swimming protocols, both interval and steady, and they supplemented the rats with hesperidin. The workouts were pretty intense by human standards. Either 50 minutes of continuous loaded swimming, or 50 one-minute intervals with even heavier loaded swimming.

Exercise reduces blood glucose, as you would imagine. The more intense the exercise, the lower the glucose level becomes, so the rats performing the intervals had the least glucose. Each rat that supplemented with hesperidin had even less blood glucose. This is likely due to better utilization of blood sugar by an improvement to the insulin system, and as such taking hesperidin presumably wouldn’t be a detriment to people with already low blood sugar.

The hesperidin also improved the blood profiles of other important biochemicals. For example, the rats supplementing with hesperidin had lower total cholesterol, lower LDL cholesterol (the bad kind), and lower triglycerides, but they had higher HDL cholesterol (the good kind). These changes have been associated with a reduction in metabolic diseases like diabetes, in this case not only from the exercise itself, but also from hesperidin supplementation.

Blood chemistry wasn’t the only improvement, though. Protection from cancer-causing free radicals was also increased. In the continuous swimming group, the antioxidant capacity of rats actually increased to 83% more than their non-hesperidin counterparts. The interval swimming group experienced reduced lipid peroxidation to the tune of 45%. Lipid peroxidation is the direct chemical process by which free radicals damage your cells.

No matter which exercise was performed, the protective benefits of this citrus flavonoid were clear. Not only does hesperidin help keep you safe from free radicals, but when combined with steady cardio it will actually improve your protection against future activities.

So the evidence is in. Hesperidin is good for rats. And in this case, although the numbers maybe unreliable – especially since I’d definitely drown if I had to swim weighted for 50 minutes – I think we can extend these benefits in some degree to us as well. And best of all, you can also just eat citrus fruits.


1. David Michel de Oliveira, et. al., “Hesperidin associated with continuous and interval swimming improved biochemical and oxidative biomarkers in rats,” Journal of the International Society of Sports Nutrition 2013, 10:27

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