Rich in iron and a true slow-aging food: 6 reasons why you should eat more olives

Black olives: What makes them so healthy – and how many you should eat per day.

"Black olives are much more than just an appetizer," says Yaraseth del Castillo, nutritionist at the Medical Anti-Aging Institute (Madrid). "They are a functional food with antioxidant, anti-inflammatory, and cardioprotective properties. They provide healthy monounsaturated fats, especially oleic acid, which helps reduce systemic inflammation and protect the cardiovascular system. They are also an excellent source of vitamin E, iron, and fiber , and are characterized by their high content of phenolic compounds such as oleuropein and hydroxytyrosol, both of which have potent neuroprotective and anti-aging effects."

According to del Castillo, the phenolic compounds in black olives are particularly valuable during periods such as perimenopause and menopause – "that is, during periods when the female organism experiences increased oxidative stress, greater metabolic instability, and inflammatory changes, which can be partially and precisely modulated by diet," the expert adds.

Black olives are not (that) black in reality

There are more than 200 varieties of olives, but in Spain, the main supplier of olives, there are three main types of olives whose coloring varies depending on when they are harvested: green olives, which are picked from the tree before they are ripe; variable olives (purple, pink, or chestnut-brown olives), which are harvested when they are almost but not quite ripe; and black olives, which are harvested when ripe but only acquire their intense color after the processing process," explains Yaraseth del Castillo. The black coloring is the result of the addition of ferrous gluconate (E579) or ferrous lactate (E585).

In fact, there are no completely black olives in nature, like those sold in supermarkets. True "black" olives, i.e., those that aren't dyed, exhibit various shades of color, from brown to reddish—they are never jet black and rarely have a uniform hue.

To find out whether they are real black olives or "colored olives," it is enough to read the label, which, according to the law, must contain the alphanumeric codes of the ingredients mentioned, in this case, as already mentioned, E579 or E585.

Are colored olives unhealthy?

No, according to nutritionist Yaraseth del Castillo, black-tinted olives are not harmful. However, true black olives, those that are actually more reddish-brown, are preferable due to their health benefits, which black-tinted olives cannot match.

This is what makes real black olives so healthy:

Now let's take a look at the health benefits of black olives and why nutritionists like Yaraseth del Castillo recommend including them in our diet.

#1 Black olives are rich in iron

"Black olives contain more iron than green olives, which is particularly beneficial for people prone to anemia or chronic fatigue," says the expert.

#2 They contain many antioxidants

"Black olives also have a higher concentration of hydroxytyrosol, one of the most bioavailable antioxidants ," explains the nutritionist. In addition, olives of all kinds are a source of vitamin E, which helps protect cells from oxidative damage.

#3 They help reduce body fat

As if that weren't enough, the specialist at the Anti-Aging Medical Institute points to a 2024 study by the University of Granada that identified a compound found in black olives, β-resorcylic acid. According to the study, β-resorcylic acid is capable of reducing fat mass without affecting muscle mass, improving insulin resistance, and boosting metabolism. "This discovery opens new avenues in the prevention of metabolic diseases through functional nutrition," says Yaraseth del Castillo.

#4 Black olives help prevent colon and rectal cancer

Yaraseth del Castillo also points out that studies have shown that olive peel components can reduce the formation of colon polyps by 45%, making them interesting for the prevention of colon cancer.

#5 They help keep cholesterol levels under control.

Olives are rich in oleic acid (up to 77%), an unsaturated fatty acid that helps maintain normal blood cholesterol levels.

#6 Black olives are rich in probiotics (when preserved in brine).

Olives are inedible raw because they contain many bitter compounds . Conventionally, they are treated with caustic soda and then fermented with added lactic acid bacteria, which improves flavor and shelf life. Organic olives are usually simply soaked in salt water—a slower but gentler method that preserves natural lactic acid bacteria. These have a probiotic effect, promote intestinal health , and strengthen the immune system . Industrially processed olives lose these health benefits, which is why artisanal or organic versions are recommended.

How many black olives should you eat per day?

Many nutritionists recommend consuming approximately 25 grams of olives—equivalent to about seven olives per day, seven days a week. Olives are often claimed to be high in calories. However, the recommended amount contains only 37 calories. According to Yaraseth del Castillo, this is a satisfying and beneficial dose—"when choosing natural varieties fermented in brine and low in salt."

The expert points to a 2022 study from the Harvard TH Chan School of Public Health , which shows that regular consumption of olive oil (and therefore olives) significantly reduces the risk of death from cardiovascular disease, cancer, and neurodegenerative disorders. So the next time you're offered olives at a bar, take them.

This article originally appeared on VOGUE.es

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