Does Coffee Affect Vitamin Absorption?

Erin Coleman, R.D., L.D.
Friends drinking coffee

Research suggests drinking coffee affects the absorption of certain nutrients by inhibiting them. The Linus Pauling Institute says coffee lowers calcium and iron absorption in your body, and MedlinePlus reports coffee inhibits the absorption of thiamin, also known as vitamin B1.

How Much Coffee Is too Much?

While there's no official guidelines stating how much coffee you should drink (except during pregnancy), several recommendations do exist.

  • The National Osteoporosis Foundation says drinking more than three cups of coffee daily may reduce calcium absorption and lead to bone loss.
  • The Linus Pauling Institute says one cup of coffee reduces calcium absorption by 4 to 6 milligrams and also recommends limiting coffee to three cups daily to reduce bone loss and fractures.
  • The Iron Disorders Institute says drinking just one cup of coffee daily may lower iron absorption by up to 60 percent.

So, a good rule of thumb is to drink three cups of coffee or fewer daily to minimize vitamin malabsorption.

Why Effects on Absorption Occur

There are several reasons drinking coffee may reduce the absorption of calcium, iron, and thiamin. MedlinePlus says tannins in coffee react with vitamin B1, converting it into a form of the vitamin that's more difficult for your body to absorb. The National Osteoporosis Foundation reports caffeine in coffee may lower calcium absorption, and the Iron Disorders Institute suggests polyphenols present in coffee inhibit iron absorption.

Ways to Prevent Malabsorption

Just because coffee can lower absorption rates of certain vitamins and minerals doesn't mean you have to give up your daily coffee fix.

  • Limit intake: Limiting coffee consumption to three cups daily is the best way to ensure you're not overdoing it.
  • Get plenty of vitamin C: Likewise, getting plenty of vitamin C appears to prevent malabsorption effects from coffee on thiamin, notes MedlinePlus. Vitamin C also enhances iron absorption, which helps counteract coffee's effects on iron.
  • Avoid coffee within two hours of eating iron-rich foods or taking iron supplements: The Iron Disorders Institute says to avoid drinking coffee within two hours of eating an iron-rich meal or taking iron supplements to maximize absorption rates.
  • Switch to decaf: To minimize calcium losses, try decaf coffee or swap at least one of your daily cups to decaf, and get plenty of calcium and vitamin D in your diet, suggests the Linus Pauling Institute.

Should I Drink Coffee?

From reducing disease risks to aiding in healthy weight management, coffee appears to provide you with numerous health benefits. So if you're a coffee lover, don't stop drinking it. Simply follow a few simple tips to maximize vitamin and mineral absorption while drinking coffee. If you're unsure about your coffee intake and how it might be affecting your health, speak with your doctor.

Does Coffee Affect Vitamin Absorption?