Sickle cell disease and macronutrients: Building blocks of your diet

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Learn about the nutrients that help your body function, including their role in the body and which foods are richest in these nutrients.

Key points

  • The two main types of nutrients are micronutrients and macronutrients. Micronutrients are eaten in small quantities, and macronutrients are eaten in large quantities.
  • Micronutrients include vitamins A, C and D, and minerals such as calcium, iron and magnesium.
  • There are three macronutrients—fat, protein and carbohydrates—and each plays an important role in your body.
  • A healthy diet is very important to keep your body functioning at its best. Try to regularly eat a range of nutritious foods from all food groups, and limit the amount of bad fats, sweets and highly processed foods you eat.

All the food you eat contains nutrients, the substances that help your body function. There are two main types of nutrients:

  1. micronutrients
  2. macronutrients

Micronutrients are nutrients that you eat only in small quantities (“micro” means very small). They include vitamins such as vitamins A, C and D, and minerals such as calcium, iron and magnesium, to name just a few.

Macronutrients are the big building blocks of your diet—you eat these nutrients in large quantities (“macro” means large).

There are three macronutrients:

  1. fat
  2. protein
  3. carbohydrates

Each of them plays an important role in your body.


Among other things, fat:

  • gives you energy while you are resting or doing low-intensity exercise
  • helps your body absorb vitamins A, D, E and K (these vitamins need fat to transport them around the body)
  • provides essential fatty acids. These are fats that the body needs from your diet to keep the heart healthy, help the brain function properly, make hormones and build healthy cells and skin.

Over the years, you might have heard to avoid “fatty foods”. However, not all foods that are high in fat are bad. This is because there are good fats and bad fats.

Good fats

Fish such as salmon, for example, are generally a source of good fat, especially omega-3 fatty acids. Other sources of good fats include nuts and seeds, vegetable oils and avocados.

You may hear that fish can contain high levels of mercury. It is true that, over time, mercury can build up in some larger fish like white tuna, shark and swordfish. It’s better to avoid these larger fish, but it’s safe to eat most others, including salmon, cod, haddock and sole.

Bad fats

Unhealthy fats include trans-fat and saturated fat. These fats should be limited because they can increase your risk of heart disease. To reduce the amount of unhealthy fats in your diet, limit foods such as butter, hard margarine, lard and shortening (found in pastries), fatty cuts of meat, and chicken with the skin on.

Pay attention to nutrition claims

Be careful when you see food products that are advertised as “low fat”. Often, food manufacturers will add extra sugar, sweeteners or salt to make the food taste better. Over time, these added ingredients may be worse for you than the fat the manufacturer removed from the food.

Talk to your health-care team or a registered dietitian about how to make healthy choices about low-fat food products.


Protein plays a number of roles in the body, including:

  • building and repairing muscles, blood cells, organs, bones, skin, hair and nails
  • helping muscles work
  • helping to make enzymes to digest food
  • helping to make hormones to control things such as your appetite, sleep and mood

People with sickle cell disease may need more protein to help make extra red blood cells.

Another benefit of protein is that it helps you feel full for longer. Starting your day with a good source of protein, such as eggs, and including protein in every meal will help to keep hunger at bay and make you less likely to snack mindlessly. It will also help you concentrate at school or work.

The food groups richest in protein are:

  • meat and alternatives, which includes chicken, beef, eggs, tofu, beans, peas and lentils
  • milk and alternatives, which includes dairy, almond and rice milk, yogurt and different types of cheese.


Carbohydrates play two main roles in the body.

  1. They are the body’s main source of fuel (energy).
  2. They provide fibre to help food pass through the digestive system and help keep you fuller longer.

The food groups richest in carbohydrates are:

  • grain products, such as bread, pasta, rice, barley and oats
  • vegetables and fruit

Some people might fear certain “high-carb foods” (usually made from grain products) because they believe that they lead to weight gain or bloating. But this belief ignores the different types of carbohydrates and how they behave in the body. It also ignores the fact that many people can have healthy amounts of carbohydrates for their individual needs without any problems.

There are two main types of carbohydrates:

  1. simple carbohydrates
  2. complex carbohydrates

Simple carbohydrates (sugars) are those in foods such as fruit juice, honey, sugar and candy. These foods tend to cause blood sugar levels to “spike” (rise very quickly) and then fall quickly, which can leave you feeling hungry soon afterwards.

Complex carbohydrates (starches) are found in grains, vegetables and legumes (beans, peas and so on), and whole fruit. These foods are filled with fibre and are digested more slowly, meaning that they keep you full for longer.

There is a place for simple and complex carbohydrates in your diet. For example, many fruits (such as strawberries, cherries, grapes and raisins) can help ease inflammation. Apples also boost acetylcholine in the brain, a chemical that helps with memory, concentration and energy. That said, it is best not to rely on simple carbohydrates for your energy. This includes juices and soft drinks, which often contain high amounts of sugar and sweeteners.

When it comes to choosing complex carbohydrates, aim for whole grains such as barley, wholewheat pasta and wholegrain bread, and try to eat a wide range of vegetables.

Last updated: November 6th 2023