The pith (white part) of citrus contains what is known as hesperidin which may be a valuable nutrient to help lower blood pressure and cholesterol.
Naringin, on the other hand, a flavonoid that occurs naturally in citrus fruits, especially in Grapefruits is what gives them their bitter taste.
Hesperidin and naringin both play important roles in preventing the development of hyperglycemia and therefore are good for regulating blood glucose levels.
Unfortunately in commercially made grapefruit juice the bitterness of naringin is often removed for a milder tasting beverage and depending on the method of debittering, this can cause the removal of vital nutrients like hesperidin and reduction of vitamin C content. This is one of the reasons why it is so important to consume foods as fresh as possible.
This is not to say that one should start eating lots of bitter oranges and lemons with the pith to the point that you can’t taste anything else. Only that next time you have an orange, it’s okay to not peel all of the white pith. Remember that enjoying fresh, zesty flavours can increase the nutrients you consume.
Limonene, another substance found in citrus peel oil, may have some cancer-preventing properties depending on the type of cancer. We’ll discuss this in a later post, stay tuned!
References
https://cancerpreventionresearch.aacrjournals.org/content/canprevres/6/6/577.full.pdf
https://cancerres.aacrjournals.org/content/canres/52/14/4021.full.pdf
https://academic.oup.com/jn/article/134/10/2499/4688346
https://academic.oup.com/advances/article/5/4/404/4568623
https://www.researchgate.net/publication/223730830_Effects_of_debittering_on_red_grapefruit_juice