Donating blood is a relatively safe way to help people with serious medical conditions. Donating blood can lead to some side effects, though, like fatigue or anemia. Eating and drinking the right things before and after donating can help reduce your risk for side effects.

Read on to learn what you should eat and drink before donating blood, plus learn tips for things you can do after you donate.

If you’re donating blood, it’s important to stay hydrated before and after you donate. That’s because about half of your blood is made of water. It’s also good to increase your iron intake because you lose iron when you donate. Low iron levels can cause symptoms of fatigue.

Iron

Iron is an important mineral your body uses to make hemoglobin. Hemoglobin is responsible for carrying oxygen from your lungs to the rest of your body.

Eating a well-balanced diet with plenty of iron-rich foods can help you store extra iron. If you don’t have enough iron stored away to make up for the iron you lose when donating blood, you can develop iron deficiency anemia.

There are two different types of iron found in foods: heme iron and nonheme iron. Heme iron is more easily absorbed, so it boosts your iron levels more effectively. Your body absorbs up to 30 percent of heme iron and only 2 to 10 percent of nonheme iron.

Before you donate blood, consider increasing your intake of iron-rich foods. This can help increase the iron stores in your body and reduce your risk for iron deficiency anemia.

Foods rich in heme iron include:

  • Meats, like beef, lamb, ham, pork, veal, and dried beef.
  • Poultry, such as chicken and turkey.
  • Fish and shellfish, like tuna, shrimp, clams, haddock, and mackerel.
  • Organs, such as liver.
  • Eggs.

Foods rich in nonheme iron include:

  • Vegetables, such as spinach, sweet potatoes, peas, broccoli, string beans, beet greens, dandelion greens, collards, kale, and chard.
  • Breads and cereals, including enriched white bread, enriched cereal, whole-wheat bread, enriched pasta, wheat, bran cereals, cornmeal, oats, rye bread, and enriched rice.
  • Fruits, such as strawberries, watermelon, raisons, dates, figs, prunes, prune juice, dried apricots, and dried peaches.
  • Beans, including tofu, kidney, garbanzo, white, dried peas, dried beans, and lentils.

Vitamin C

Although heme iron will raise your iron levels more effectively, vitamin C can help your body better absorb plant-based iron, or nonheme iron.

Many fruits are a good source of vitamin C. Fruits high in this vitamin include:

  • cantaloupe
  • citrus fruits and juices
  • kiwi fruit
  • mango
  • papaya
  • pineapple
  • strawberries
  • raspberries
  • blueberries
  • cranberries
  • watermelon
  • tomatoes

Water

Around half of the blood you donate is made of water. This means you’ll want to be fully hydrated. When you lose fluids during the blood donation process, your blood pressure can drop, leading to dizziness. The American Red Cross recommends drinking an extra 16 ounces, or 2 cups, of water before donating blood. Other nonalcoholic beverages are fine, too.

This extra fluid is in addition to the recommended 72 to 104 ounces (9 to 13 cups) you should drink each day.

Certain foods and beverages can have a negative effect on your blood. Before donating blood, try to avoid the following:

Alcohol

Alcoholic beverages lead to dehydration. Try to avoid drinking alcohol 24 hours before giving blood. If you do drink alcohol, make sure to compensate by drinking extra water.

Fatty foods

Foods high in fat, such as french fries or ice cream, can affect the tests that are run on your blood. If your donation can’t be tested for infectious diseases, then it can’t be used for transfusion. So, skip the doughnuts on donation day.

Iron blockers

Certain foods and beverages can affect your body’s ability to absorb iron. You don’t have to avoid these foods completely, but avoid eating them at the same time you consume iron-rich foods or iron supplements. Foods that reduce iron absorption include:

  • coffee and tea
  • high-calcium foods like milk, cheese, and yogurt
  • red wine
  • chocolate

Aspirin

If you’re donating blood platelets — which is a different process than donating whole, or regular, blood — your system must be aspirin-free for 48 hours prior to donation.

After you donate blood, you’ll be provided with a light snack and something to drink. This will help stabilize your blood sugar and fluid levels. To replenish your fluids, drink an extra 4 cups of water over the next 24 hours, and avoid alcohol.

Most people experience no side effects when giving blood. After donating blood, you’ll be asked to wait in the refreshments area for 10 to 15 minutes to make sure you’re feeling OK.

Once you’ve had a snack and something to drink, you can return to your daily activities. The Red Cross recommends avoiding heavy lifting and vigorous exercise for the rest of the day.

If you’re a frequent blood donor, you may want to talk to your doctor about iron supplements. It can take months for your iron levels to return to normal after giving blood. A 2015 study found that taking iron supplements can significantly reduce this recovery time.

Donating blood is a great way to give back to your community. It’s usually quick and easy. If you eat healthy on the day of your donation and drink plenty of extra fluids, you should have minimal or no side effects.