1. Tomatoes + Olive Oil
Lycopene — a carotenoid antioxidant that gives fruits and vegetables like tomatoes and watermelon a pink or red color — is one of the key reasons why tomatoes are so good for you.
However, when you eat tomatoes with olive oil, the antioxidant activity of the lycopene is increased.2 Lycopene is a fat-soluble nutrient, which means eating it with some dietary fat is essential in order for it to be properly absorbed. But this doesn't explain the whole picture.
When researchers combined tomatoes with sunflower oil, the activity of lycopene did not increase, which suggests there's something especially beneficial about the olive oil.
If you're a fan of tomato sauce, you're in luck as well, as lycopene is one example of a nutrient that becomes more bioavailable when it's cooked. Research shows that cooking tomatoes (such as in tomato sauce or tomato paste) increases the lycopene content that can be absorbed by your body.
It also increases the total antioxidant activity. So one of the healthiest ways to consume tomatoes may be in an organic tomato sauce, drizzled with organic olive oil.
2. Wild-Caught Salmon + Collard Greens
Vitamin D helps your body to absorb calcium. In fact, if you have a vitamin D deficiency, it can cause a defect in putting calcium into the collagen matrix in your skeleton, leading to aches and pains.
In addition to being rich in vitamin K and phytonutrients that may help lower oxidative stress, fight inflammation, and prevent cancer, collard greens are rich in calcium. Wild-caught Alaskan salmon, meanwhile, contains some vitamin D, so consuming them together could theoretically be beneficial.
Wild-caught Alaskan salmon is high in healthy omega-3 fats and low in hazardous contaminants, and has about 988 IUs of vitamin D per 3.5-ounce serving.
It's important to note that farm-raised salmon does not have nearly this level of vitamin D, with only 245 IUs per 3.5-ounce serving.3
It is difficult, however, to get optimal levels of vitamin D from your diet alone, and a better solution is to get sensible exposure to the sun or a high-quality tanning bed.
This will ensure you have adequate vitamin D levels to absorb the dietary calcium you consume.
If you decide to take a vitamin D supplement, keep in mind that it will increase your body's need for vitamin K2. So when supplementing with oral vitamin D3, you need to make sure you're also increasing your K2 and magnesium intake.
The biological role of vitamin K2 is to help move calcium into the proper areas in your body, such as your bones and teeth. It also helps remove calcium from areas where it shouldn't be, such as in your arteries and soft tissues.
So vitamin K2 deficiency is actually what produces the symptoms of vitamin D toxicity, which includes inappropriate calcification that can lead to hardening of your arteries. If you want a natural dietary source of vitamin K2, fermented vegetables made with Kinetic Culture will produce high levels of K2.
3. Broccoli + Tomatoes
In addition to lycopene, tomatoes are an excellent source of lutein, zeaxanthin, and vitamin C (which is most concentrated in the jelly-like substance that surrounds the seeds), as well as vitamins A, E, and the B vitamins, potassium, manganese, and phosphorus.
Broccoli, meanwhile, is rich in vitamin K, vitamin C, folate, fiber and cancer-fighting compounds like sulforaphane. When rats were fed diets containing 10 percent broccoli, they had a 42 percent decrease in the growth of prostate cancer tumors.
When they were fed a diet containing 10 percent tomatoes, the growth rate dropped by 34 percent.
But when the rats were fed a diet with 10 percent broccoli and 10 percent tomatoes combined, the tumor weights decreased by 52 percent.4 So add some steamed broccoli to your tomato sauce or some raw broccoli and chopped tomatoes to your salad to boost their health potential.
4. Green Tea + Black Pepper
Black pepper contains a substance called piperine, which not only gives it its pungent flavor, but also blocks the formation of new fat cells.5 When combined with capsaicin and other substances, black pepper was also found to burn as many calories as taking a 20-minute walk.6
As an aside, black pepper also increases the bioavailability of just about all other foods -- herbs and other compounds included. Green tea, for instance, is recognized as an abundant source of epigallocatechin-3-gallate (EGCG), a catechin polyphenol shown to boost metabolism and protect against cancer.
Research shows that when EGCG is administered in combination with piperine, it increases the absorption of EGCG and helped it stay in the bloodstream longer. If the idea of sprinkling black pepper in your tea isn't appealing, TIME suggests:7
"Use the pair to soak meat or seafood. 'Brewed tea with garlic, ginger, and black pepper makes a perfect marinade,' [Cynthia] Sass [RD, MPH] says."
5. Turmeric + Black Pepper
Turmeric, the yellow-pigmented "curry spice" often used in Indian cuisine, contains curcumin, the polyphenol identified as its primary active component and which exhibits over 150 potentially therapeutic activities, which include antioxidant, anti-inflammatory, and anti-cancer properties.8
Black pepper or piperine is sometimes added to turmeric because it's believed to "heat up" the digestive system, which may help increase absorption. According to Melissa Rifkin, RD, a bariatric dietitian at Montefiore Medical Center in New York City, "If you pair the turmeric with the piperine, it improves the bioavailability of curcumin by 1000 times." 9
6. Brussels Sprouts + Olive Oil
Brussels sprouts contain sulfur-containing compounds called glucosinolates, which your body uses to make isothiocyanates. These activate cancer-fighting enzyme systems in your body. Brussels sprouts have been linked to the prevention of a number of cancers, including colon cancer,10 ovarian cancer,11 and others.
Brussels sprouts are also rich in vitamin K, with about 243 percent of the recommended daily value in one cup. Vitamin K is a fat-soluble nutrient, so eating Brussels sprouts along with a healthy fat like olive oil will help increase its absorption. Rich in monounsaturated fats, olive oil may help lower your risk of heart disease and may even benefit insulin levels and blood sugar control, helping to lower your risk of type 2 diabetes.
7. Kale + Almonds
Just one cup of kale will flood your body with disease-fighting vitamins K, E, A, and C, along with respectable amounts of manganese, copper, B vitamins, fiber, calcium, and potassium. With each serving of kale, you'll also find more than 45 unique flavonoids, which have both antioxidant and anti-inflammatory benefits.12
Vitamins K, E and A are fat-soluble, which is where the almonds come in to help ensure proper absorption. Almonds contain healthy monounsaturated fat, although one of the healthiest aspects of almonds appears to be their skins, as they are rich in antioxidants including phenols, flavonoids, and phenolic acids, which are typically associated with vegetables and fruits.
A study in the Journal of Agricultural and Food Chemistry even revealed that a one-ounce serving of almonds has a similar amount of total polyphenols as a cup of steamed broccoli or green tea.13 Almonds pair well with kale, for example slivered almonds atop a kale salad. However, any nut will do. My personal favorites are macadamia nuts and pecans.
8. Dark Chocolate + Apples
Eating apples is associated with a lower risk of death from heart disease, an association that's thought to be related to their content of antioxidant flavonoids,14 including the anti-inflammatory quercetin. Dark chocolate, which is rich in antioxidant catechins, has also been found to support heart health. In one study, the highest levels of chocolate consumption were associated with a 37 percent reduction in cardiovascular disease and a 29 percent reduction in stroke compared with the lowest levels.15 According to Rifkin:
"When paired, they [dark chocolate and apples] have been shown to help break up blood clots."
A couple of caveats… because much of the antioxidant content of an apple is found in its peel, you'll want to leave the peel on when you eat it. For this reason, look for organic apples, which will be free from pesticides and other chemicals. For chocolate, the closer your cocoa is to its natural raw state, the higher its nutritional value. Ideally, your chocolate or cocoa should be consumed raw (cacao). When selecting chocolate, you can optimize its nutritional punch by looking for higher cacao and lower sugar content.
In general, the darker the chocolate, the higher the cacao. However, cacao is fairly bitter, so the higher the percentage cacao, the more bitter it is (the flavanols are what make the chocolate bitter, so manufacturers often remove them. But, it's those flavanols that are responsible for many of chocolate's health benefits). To counteract the bitterness, most chocolate is sweetened, so it's a matter of balancing nutritional benefit with palatability.
9. Garlic + Wild-Caught Alaskan Salmon
A study published in the American Journal of Nutrition found that in men with high cholesterol, those who consumed 900 milligrams of garlic and 12 grams of fish oil decreased LDL cholesterol by 9.5 percent.16 It's thought that eating wild-caught salmon with garlic may offer similar benefits, although you probably won't be eating it every day, which is where an animal-based omega-3 fat supplement like krill oil can be beneficial.
Still, garlic is rich in manganese, calcium, phosphorus, selenium, and vitamins B6 and C, so it's beneficial for your bones as well as your thyroid. It's thought that much of garlic's therapeutic effect comes from its sulfur-containing compounds, such as allicin, which are also what give it its characteristic smell. Garlic also has antibacterial, antiviral, and anti-fungal properties, making it one food that's beneficial to consume as often as you like.
10. Black Beans + Red Bell Pepper
Black beans are a good source of non-heme iron (the kind found in plants), which is more difficult for your body to absorb. Combining black beans with a vitamin-C-rich food, like red bell pepper, may increase the absorption of non-heme iron by six times. Some people, particularly men and post-menopausal women, may have problems with elevated iron levels. I recommend checking your iron levels regularly using a simple blood test called a serum ferritin test; your ferritin level should be between 20 and 80 ng/ml, and 40 to 60 is ideal. If your iron levels are elevated, donating blood is one of the best solutions.
There are other reasons to eat black beans and peppers outside of the iron, of course. Black beans are a good source of folate, dietary fiber, manganese, protein, magnesium, vitamin B1 (thiamin), phosphorus, and antioxidants. Bell peppers, aside from being rich in vitamin C, also contain vitamin K, thiamin, niacin, folate, magnesium, and copper, along with phenolic compounds and antioxidant carotenoids.