Researchers at the University of Missouri have demonstrated that how we combine foods on a plate directly affects how many nutrients the body ultimately absorbs. The bioavailability of vitamins and other nutrients largely depends on what other ingredients are in the dish: some combinations significantly enhance it, while others reduce it.
This is especially true for fat‑soluble components, such as vitamins A, D, E, and K, as well as carotenoids. They are absorbed only in the presence of fats. For example, adding olive oil to carrots increases the absorption of beta‑carotene sixfold. A dressing based on oil or avocado can boost the uptake of beneficial compounds from vegetables by 7 to 18 times. Therefore, even a simple salad made with carrots or tomatoes will be much more beneficial if enhanced with these ingredients.
A notable example is kale. It is often called a “superfood” due to its high content of vitamins and antioxidants. However, according to a University of Missouri study, raw kale releases carotenoids poorly, and the situation becomes even worse after cooking. The effect changes dramatically with an oil‑based dressing, regardless of whether the oil is added to the cooked leaves or the kale is prepared directly in the sauce.
Another scientifically supported beneficial pairing is turmeric and black pepper. Piperine, a compound found in pepper, greatly increases the bioavailability of curcumin — the active ingredient in turmeric. Animal studies have shown that when consumed together, curcumin concentrations in the blood remain significantly higher even after 24 hours. Researchers are now testing this effect in clinical trials, particularly to determine whether this combination could be useful in treating inflammatory conditions.
Spinach is a rich source of iron, but its absorption is hindered by oxalates. Vitamin C helps neutralize their effect by promoting the conversion of iron into a form that the body can more easily use. Drizzling spinach with lemon juice can notably improve absorption. According to Harvard University data, vitamin C can increase the uptake of plant‑based iron by 2 to 3 times. The same principle applies to other vitamin C‑rich foods, such as oranges or bell peppers.
The method of cooking is also important. Heat treatment helps release certain beneficial compounds: for example, lycopene from tomatoes and beta‑carotene from carrots become more available to the body. However, moderation is key: prolonged boiling or frying destroys water‑soluble vitamins, primarily vitamin C and B‑group vitamins. Vitamin C is particularly heat‑sensitive: its degradation starts at temperatures above 60 °C. For instance, boiling cabbage can lead to a loss of up to 90 % of this vitamin, Agrotime reports.
Moreover, the nutrient content may also depend on the variety of the product. Different types of tomatoes, for example, vary in their composition. Dietitian, psychotherapist, and PhD Andrey Bobrovsky explained this in an interview with Vechernyaya Moskva, detailing the beneficial properties of various tomato varieties.
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