Dietitians say some healthy foods should be avoided as we age or when we are taking common drugs — and could even be dangerous for some people. According to dietitians healthy foods can interfere with common drugs that millions of us take as we get older.

Sarah Hormachea, registered dietitian at Nourish, told HuffPost: “Grapefruit and grapefruit juice are known to interfere with statins, which are used to reduce cholesterol. A compound in grapefruit called furanocoumarins competes with the enzyme in our liver that is used to metabolize statin medications.”

Dietitian Maria Emerick said grapefruit can also interact with blood thinners like warfarin ‘increasing the risk of side effects or toxicity’.

Grapefruit can also interfere with drugs used for blood pressure, heart defects, and depression or anxiety. Maria said some people should also consider avoiding food like kale and spinach, adding,“Foods rich in vitamin K can interfere with the effectiveness of blood thinners like warfarin.”

And Shelley Balls, registered dietitian and nutritionist for Consumer Health Digest, said vitamin K can interfere with antacids, antibiotics, aspirin and drugs for cancer, seizures and high cholesterol.

Foods rich in vitamin K include:

Leafy Green Vegetables (Highest Sources)

  • Kale
  • Spinach
  • Collard greens
  • Swiss chard
  • Mustard greens
  • Turnip greens

Other Vegetables

  • Broccoli
  • Brussels sprouts
  • Cabbage
  • Asparagus
  • Green beans

Herbs (Surprisingly High in Vitamin K)

  • Parsley
  • Basil
  • Cilantro

Fruits (Moderate Amounts)

  • Prunes
  • Blueberries
  • Grapes
  • Kiwi

Animal-Based Sources

  • Liver (beef, chicken)
  • Egg yolks
  • Dairy (cheese, butter)

Fermented Foods

  • Natto (fermented soybeans, extremely high in vitamin K2)
  • Sauerkraut

Oils (Rich in Vitamin K)

  • Soybean oil
  • Canola oil
  • Olive oil