CHAPTER 10 LESSON 2: FAT-SOLUBLE VITAMINS

Retinoids

A class of chemical compounds that are vitamers of vitamin A.

Fat-Soluble

A compound or molecule that can be dissolved into fat. Vitamins A, D, E, and K are the fat-soluble vitamins. Because of their solubility, they are stored in the tissues of the body and play critical roles in metabolism and proper hormonal function.

Vitamin K

A family of compounds that have a similar structure and function - they are involved in regulating blood clotting as well as calcium metabolism.

Vitamin D

A fat-soluble vitamin present in very few foods - much of the vitamin D found in our bodies comes from the conversion of cholesterol from direct exposure to sunlight. This makes it unique among the fat-soluble vitamins in that dietary sources are often not sufficient to maintain adequate levels. Sunlight and/or supplementation is necessary.

Retinoic Acid

A metabolite of vitamin A that mediates the functions of vitamin A required for growth and development.

Compound

A thing that is composed of two or more separate elements.

Retinol

Also known as Vitamin A, retinol helps in vision, bone growth, reproduction, growth of epithelium, and fighting infections.

Retinal

Also known as retinaldehyde, one of many forms of vitamin A.

Figure: Fat-Soluble Vitamins

Because these vitamins can be stored in tissues, vitamin toxicity from high intakes is also possible and diets that are high in fat-soluble, vitamin-rich foods should be monitored. When talking to clients about their nutrition, careful attention should be given to ensuring adequate levels of fat-soluble vitamin intake through the variety of foods suggested in this chapter.

What can a client incorporate into their diet to minimize the chances of becoming deficient in fat-soluble vitamins? Check all that apply. Consume several servings of carbohydates (2-3) per day. Consume fatty fish at least once a week. Consume several servings of vitamin rich nuts and seeds (2-3) per day. Consume several servings of fortified dairy products (2-3) per day.

Consume fatty fish at least once a week. Consume several servings of vitamin rich nuts and seeds (2-3) per day. Consume several servings of fortified dairy products (2-3) per day.

What is required for the body to absorb fat-soluble vitamins? Proteins Water Fats Carbs

Fats

Common Food Sources of Vitamins Summary

Micronutrients are core components of all the foods that we consume. They give many foods their taste and color and should not be viewed much differently than macronutrients as they co-occur. When helping support a client with their nutrition, it is important to consider both the quantity and quality of the diet. When supporting an RDN who may have created this diet for the client, the key is to understand how best to support the client in their quest to make better food choices. The B-complex vitamins, folate, and vitamin C are found in a wide range of food sources. Vitamins B1, B2, B3, B5, B7, B12, and folate are all found in fortified grain products such as cereals, breads, and pastas. Vitamin B2 (riboflavin) is also found in milk and most organ meats (e.g., liver and kidney) while vitamin B3 (niacin) is found in beef, fish, and poultry. Vitamin B5 (pantothenic acid) is found in beef, poultry, organ meats, and eggs, as well as oatmeal and potatoes. Folate can also be found in leafy, green vegetables while biotin is found in small quantities in some fruits and beef and in moderate amounts in liver. Vitamin C is found primarily in fruits, specifically citrus fruits; however, it can also be found in dark, leafy greens, cruciferous vegetables, and tomatoes. Lightspring/Shutterstock.com Fat-soluble vitamins are found in similar food sources as the water-soluble vitamins. Vitamin A is found in dark, leafy greens and dark-colored fruits, in high quantities in fish and liver, and in moderate quantities in milk products (e.g., milk and yogurt). Vitamin D is found in fatty fish (e.g., salmon, herring, and sardines), fish oils (e.g., cod liver oil), fortified cereal products, and fortified milk products. Vitamin E is in nuts and seeds (e.g., almonds, nuts, and sunflower seeds) and their cold-pressed oils, fruits and vegetables, and beef. Vitamin K is primarily in dark, leafy greens and some plant oils. Food For Thought When considering the major food sources of both water- and fat-soluble vitamins, it is abundantly clear that a diet rich in fruits; dark,-green, leafy vegetables; animal meats; and dairy will allow people to reach their micronutrient needs. Enriched and fortified grains and cereals are used to help offset diets that are missing in these food groups.

Match the fat-soluble vitamin with its respective benefit. To begin, click an item in the left column. Then, click the matching answer in the column on the right. Vit A Vit K Vit D Vit E

Vit A - Critical for vision, immune, function, and for human development Vit K - Regulates blood homeostasis by controlling clotting Vit D - Critical for immune function, bone formation, and calcium metabolism Vit E - Protect cells from oxidative damage

Where is it found in foods? Vitamin A

Vitamin A is found primarily in fish, specifically fish oils such as cod liver oil. It is also found in butter, eggs, some cheeses, and beta-carotene-rich foods such as carrots, squash, and kale. How do we apply this information? Vitamin A is consumed in adequate quantities when following a balanced diet that includes some seafood; dairy; green, leafy vegetables; and bright-colored vegetables. In cases where vitamin A deficiency is a concern, a registered dietitian nutritionist can help with supplementation guidelines after the adequate dietary sources are incorporated regularly.

Where is it found in foods? Vitamin D

Vitamin D is found in many of the same foods as vitamin A: salmon, sardines, mackerel, tuna, cod-liver oil, shiitake mushrooms, fortified milk, and fortified cheese. Food For Thought Vitamin D was first discovered in cod liver oil and has since been identified as an essential vitamin and an important nutrient for a variety of metabolic and biological processes. How do we apply this information? Of all the micronutrients, vitamin D has the highest rate of deficiency worldwide. Specific focus should be given to this micronutrient to ensure that there are not substantial deficiencies and to encourage more vitamin D-rich foods in the diet. Encouraging clients to ask their own doctor to add vitamin D to their normal labs is a wise idea as well to assess their own status. Then, the provider can make suggestions, as needed.

What is it and why is it important? Vitamin D

Vitamin D plays many critical roles in human health, including immune function, bone formation, and calcium metabolism. One of the more well-known diseases that arises from vitamin D deficiency is rickets, which is one of the first diseases that was tied directly to a nutrient deficiency (McCollum et al., 1925). In humans, vitamin D can be manufactured in the body through the conversion of cholesterol (7-dehydrocholesterol) to the active form of vitamin D (D3) by sunlight.

Vitamin E

Vitamin E A class of compounds - the most common ones are known as the tocopherols and the tocotrienols, each of which have four types: alpha, beta, gamma, and delta. Vitamin E is one of the main antioxidant molecules in the body and it protects cells from oxidative damage.

Vitamin E What is it and why is it important?

Vitamin E deficiency can lead to neurological disorders that include uncontrolled movement and slurred speech. Furthermore, vitamin E supplementation has been shown to be beneficial on lipid peroxidation and measures of oxidative damage even in otherwise healthy people

Where is it found in foods? Vitamin E

Vitamin E is primarily found in nuts and seeds (e.g., almonds, sunflower seeds, wheat germ, hazelnuts, and pine nuts) as well as oils derived from them. It is also found in fish, such as salmon, as well as butter and avocado. How do we apply this information? Getting adequate levels of vitamin E can be achieved by consuming several servings of nuts and seeds per week, as well as fish or avocado. Most people do not need to supplement with vitamin E to obtain an adequate amount from their diet.

Where is it found in foods? Vitamin K

Vitamin K is primarily found in dark, leafy greens, such as kale, collard and mustard greens, swiss chard, mustard parsley, romaine, green-leaf lettuce, & Brussels sprouts. How do we apply this information? Vitamin K is often overlooked in peoples' diets and there should be a concerted effort to focus on vitamin K intake. This can be accomplished by consuming dark, leafy greens several times a week and/or considering supplementation.

What is it and why is it important? Vitamin K

Vitamin K is the name for a family of compounds known as the phylloquinones (vitamin K1) and menaquinones (vitamin K2). plays critical roles in bone formation and remodeling as well as working synergistically with vitamin D. Vitamin K has some interesting properties in that vitamin K1 can be obtained in the diet from plants, whereas vitamin K2 is the product of bacterial fermentation and must either be made by the gut bacteria or consumed in supplemental form, come from some animal foods, or be derived from bacteria (Elder, Haytowitz, Howe, Peterson, & Booth, n.d.). Deficiencies in vitamin K lead to bleeding disorders where people cannot stop bleeding. Additionally, vitamin K deficiency can lead to osteoporosis, which can be improved by restoring vitamin K levels

Vitamin A

group of compounds referred to as retinoids. The most common retinoids are retinol, retinal, and retinoic acid. Vitamin A can also be made from beta-carotene and other similar compounds known as the carotenoids, which are antioxidants.