Food provides so many vital nutrients for our body. But did you know that pairing certain foods together can help us to better absorb specific nutrients?
Vitamin D for calcium and phosphorus absorption
Vitamin D is technically a hormone that plays an important role in regulating levels of calcium and phosphorus in the body, which is vital for bone health.
This works by stimulating the absorption of these minerals in the intestine and calcium reabsorption by the kidneys (1). For example, roughly 30% of phosphorus absorption in the intestine has been seen to depend on vitamin D (2).
The best sources of vitamin D are the action of sunlight on the skin or supplements. Due to our limited access to sunlight during autumn and winter in the UK, the government advises a 10-microgram vitamin D supplement (3).
But vitamin D can also be found in some foods such as:
- fortified spreads, drinks and breakfast cereals
- oily fish like salmon, mackerel, trout, sardines, herring and kippers
- egg yolks
- mushrooms grown in UV light
- red meat and liver
Dairy is a great source of calcium and phosphorus.
Food pairing ideas to boost calcium and phosphorus absorption:
- vitamin D supplement and a glass of milk
- salmon and a yoghurt dressing
- scrambled eggs and grated cheese
Vitamin C for iron absorption
Iron is found in food in two main forms: haem and non-haem iron. Haem iron is found in animal-based foods like red meat and liver, whereas non-haem iron is found in eggs and in plant-based foods like beans, lentils, nuts, seeds, green leafy vegetables, dried fruit and fortified cereals.
It’s more challenging for the body to absorb non-haem iron, especially as plant-based foods contain substances that reduce iron absorption (like phytates and tannins).
One of the best ways of boosting non-haem iron absorption is to add a source of vitamin C (4).
Sources of vitamin C include:
- oranges and orange juice
- kiwis
- strawberries
- blackcurrants
- peppers
- green leafy vegetables
- potatoes
Food pairing ideas to boost iron absorption:
- orange juice and iron-fortified cereal
- peppers and mixed beans (e.g. combined in a chilli)
- spinach and lentils
Black pepper for curcumin bioavailability
The spice turmeric contains an antioxidant called curcumin.
Although the current evidence base isn’t very strong when it comes to curcumin, this antioxidant has been linked with reducing stress and inflammation in the body and possibly reducing the risk of certain diseases (5).
Although curcumin isn’t very active in the body, adding black pepper to curcumin has been seen to increase its bioavailability (i.e. its absorption and function in the body) by 2000% (5)!
Food pairing ideas to boost curcumin bioavailability:
- Adding both turmeric and black pepper to a curry or scrambled eggs
- Adding black pepper to a turmeric latte
Fat and fat-soluble vitamins
Vitamins are either water-soluble or fat-soluble, based on whether they dissolve in water or fat.
B vitamins and vitamin C are water-soluble.
Fat-soluble vitamins:
- vitamin A: important for healthy vision, immunity, skin and fertility. Food sources include offal, oily fish, dairy, eggs, peppers, carrots, sweet potato, green leafy vegetables and mango.
- vitamin D: vital for regulating calcium and phosphorus, and hence bone health. Food sources include fortified products, oily fish, eggs, UV-grown mushrooms, red meat and offal.
- vitamin E: an antioxidant that is also important for immunity, eye, and skin health. Food sources include plant-based oils, nuts, seeds and whole grains.
- vitamin K: plays an important role in blood clotting, wound healing, bone, cartilage and muscle health. Food sources include green leafy vegetables, blueberries, grapes, soybeans and soybean oil, olive and rapeseed oil, wholegrains, cashew, and pine nuts.
These fat-soluble vitamins are absorbed in the gut in the presence of fat (6).
Some foods that are a good source of fat, also provide fat-soluble vitamins, for example:
- nuts, seeds and avocados are a great source of vitamin E
- many plant-based oils (live olive, rapeseed, sunflower and soybean oil) provide vitamin E and vitamin K
- oily fish is a source of vitamin D and A
Food pairing ideas to boost fat-soluble vitamin absorption:
- sweet potato mash (vitamin A) and salmon
- wholegrain toast (vitamin E and K) and peanut butter
- spinach salad (vitamins A and K) and an olive oil dressing
Fat and lycopene bioavailability
Lycopene is a natural pigment found in food that belongs to the ‘carotenoid’ family. Carotenoids have an antioxidant effect on our body, which means that they help to prevent or reduce damage by free radicals in the body.
Lycopene is found in (7):
- tomatoes
- watermelon
- papaya
- pink grapefruit
- pink guava
Lycopene is fat-soluble, so combining this with fat has been seen to improve its bioavailability (8).
For example, a small study from 2004 found that this significantly improved when a salad that contained cherry tomatoes was paired with a full-fat dressing, as compared with a low-fat dressing (9).
Heating tomato puree has also been seen to increase the availability of lycopene (10). So less fat seems to be needed to absorb heat-treated foods containing lycopene as compared with raw foods. For example, 10g of fat has been seen to optimise lycopene absorption from a meal containing processed tomato products, as opposed to 15g for raw tomatoes (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7996133/).
Food pairing ideas to boost lycopene bioavailability:
- tomatoes and olive oil
- watermelon and nuts
- papaya and full-fat greek yoghurt
