Chapter 8. Introduction to Micronutrients
Chapter Review
IMPORTANT: Key Takeaways
- Micronutrients include vitamins and minerals, which are required in smaller amounts but play vital roles in energy metabolism and various bodily functions.
- Minerals are essential to health and are obtained through the diet. Major minerals are required in amounts larger than 100 milligrams daily and include sodium, potassium, chloride, calcium, phosphorus, magnesium, and sulfur. There are 20 essential minerals that must be consumed in our diets.
- Trace minerals are minerals required in the diet (100 mg or less) and include copper, zinc, selenium, iodine, chromium, fluoride, manganese, molybdenum, and others.
- Vitamins are organic compounds, and while the body can synthesize some, there are 13 essential vitamins that must be consumed in our diets.
- Vitamins are classified as fat-soluble (vitamins A, D, E, and K) or water-soluble (vitamin C and B vitamins). Fat-soluble vitamins are found in the fatty parts of food and water-soluble vitamins are found in a variety of foods such as fruits, vegetables, dairy, meats, and whole grains.
- Water-soluble vitamins are absorbed primarily in the small intestine and transported to the liver through blood vessels while fat-soluble vitamins are absorbed along with dietary fat and packaged into chylomicrons to be transported in the lymphatic system to the liver.
- Minerals are not as efficiently absorbed as most vitamins and so the bioavailability of minerals can be very low.
- Plant-based foods contain oxalate and phytate which inhibit mineral absorption, and therefore minerals are better absorbed from animal-based foods.
- The chemical form of nutrients can also impact absorption (e.g., heme iron is better absorbed than non-heme iron).
- Some minerals impact the absorption of others (e.g., an excess intake of dietary zinc can inhibit iron and copper absorption).
Practice Questions
- Compare the storage sites and absorption of water-soluble and fat-soluble vitamins.
- Why do water-soluble vitamins need to be consumed more regularly than fat-soluble vitamins?
- How did Fiji’s government combat the national iodine deficiency? What government policies can be implemented to address the present-day mineral deficiencies in Canada?
- How are minerals classified as major minerals and trace minerals?
- How does mineral bioavailability differ between plant-based and animal-based foods? Why is this the case?
- How does chemical form affect nutrient bioavailability? Provide an example.
- What is the relationship between vitamin intake and mineral absorption? Provide an example.
