Kumquat — it’s a funny-sounding name and a cute-looking fruit, but these naturally sour, orange-colored things actually have many health benefits. They are cultivated in China, South Korea, North Korea, Taiwan, Southeast Asia, Nepal, Japan, the Middle East, Iran, and in some southern states in America. They are also known as “the little gold gems of the citrus family,” since they are tougher than oranges — withstanding both hot and freezing temperatures.

There are two maintypes of kumquats: One is called the Nagami, also known as the oval kumquat, and it’s the one most commonly found in the United States. It's oval-shaped and ranges from three quarters of an inch to 1 inch in diameter. The tree that bears this fruit is similar to an orange tree, and the fruit can hold up on to the dark green leaves for several months.

The other type is called Meiwa, also known as the round kumquat, widely grown in Japan. Even though it was introduced to the United States in 1910, it’s still pretty rare. These are sometimes referred to as sweet kumquats because they have few seeds and are tasty to eat raw. Meiwa kumquats are not recommended to be used in cooking because their flavor profile doesn’t match with the Nagami kumquats.

Despite their small differences, both of these types of kumquats have the following immense health benefits:

1. Rich in Vitamin C

Like their sister fruit, the orange, kumquats are a great source of vitamin C. They contain 73 percent of the recommended daily allowances, as per the U.S. Department of Agriculture. Vitamin C is said to protect against heart disease, high blood pressure, can boost the immune system, and is a critical vitamin in preventing degenerative diseases.

2. Antioxidant Qualities

When eating a kumquat, you don’t peel the skin, you eat the whole thing. That way, it not only cuts down the tartness, but one consumes the peel, which is rich in antioxidant properties. According to research from the National Institutes of Health, “F. margarita [kumquat] peels may be regarded as a rich source of potentially bioactive polyphenols.” Antioxidant rich foods are important for fighting the effects of free radicals, which can potentially harm cells and may play a role in the development of cancer.

3. Protein Source

You wouldn’t normally think this of a fruit, but kumquats are an excellent source of protein. One 16-ounce serving of kumquats equals up to 6.4 grams of protein. That’s a decent-sized amount for a fruit. Just combine slices of this with your favorite tree nuts, and you can skip the meat all together.

4. Might Inhibit Prostate Cancer

Research from 2012 suggested that kumquat oil could help to inhibit the growth of prostate cancer cells. “This is the first report of the identification and possible mechanisms of in vitro antiproliferative [inhibit the growth of cells] effects of kumquat volatile components on human prostate cancer (LNCaP) cells,” the research found.