Nutrients In Eggs

Vitamin A is most commonly recognized for its beneficial effects on eye health, while its other important functions are often overlooked.  As with other vitamins, there are different forms of vitamin A – one form that is most readily absorbed in the body is known as retinol, which is found in liver, eggs, and milk. Retinoids (including retinol) have many important and diverse functions throughout the body including roles in vision, regulation of cell proliferation and differentiation, growth of bone tissue, immune function, and activation of tumor suppressor genes.  These functions are especially important with respect to pregnancy and childbirth, infancy, childhood growth, night vision, red blood cell production, and resistance to infectious disease.¹

Another way for the body to get the vitamin A it needs it to convert pro-vitamin A carotenoids like beta carotene to retinol. Beta carotene is found in yellow and orange fruits and vegetables including carrots, sweet potatoes, spinach and cantaloupe.  The carotenoid form of vitamin A also provides unique health benefits. Most carotenoid forms of vitamin A function as antioxidant and anti-inflammatory nutrients. There are two forms of carotenoids that play a specific role in eye health which are known as the xanthophylls lutein and zeaxanthin.² Foods such as spinach, kale and Swiss chard are sources of foods that contain both forms of carotenoid for optimal eye health.¹ Eggs provide small amounts of lutein and zeaxanthin and research shows these nutrients in eggs may be more bioavailable (better utilized by the body) than that from sources with higher content including supplements.²

While vitamin A provides the body with many benefits, it’s important to remind clients that too much of a good thing can turn into a bad thing. Vitamin A is fat soluble which means the body stores it most often in the liver. This also means that vitamin A can build up to toxic levels in the body. This rarely happens from food sources because, if the body builds up supplies of vitamin A, it will slow down the conversion of beta carotene. Vitamin A toxicity usually occurs when people take too much in supplement or pill form. Toxic levels can cause liver problems, central nervous system problems, deterioration of bone density, and birth defects.⁴  Below is a chart that outlines the Recommended Daily Allowance (RDA) for Vitamin A as well as the upper limits.³

In addition to lutein and zeaxanthin, eggs contain the retinoid form of vitamin A and in fact, butter, cheese, and eggs are among the top 10 sources of vitamin A for U.S. adults.  Carrots, tomatoes, leafy greens, and sweet potatoes are also found in the top 10 pro vitamin A-containing foods in the U.S.⁴Try this recipe that perfectly pairs eggs with kale and sweet potatoes and get all the benefits vitamin A provides.

Eggs over Kale and Sweet Potato Grits

Servings: 4
Ingredients:

• 1 large sweet potato
• 2 cups fresh kale, chopped
• 1 tbsp vegetable oil, divided
• 1 ½ cups water
• 1 cup nonfat milk
• ¾ cup grits, quick cooking
• ¼ tsp salt
• 4 eggs

Directions

• Step 1: Heat oven to 350°F. Coat 4 individual soufflé dishes (or 2-quart casserole dish) with 1 tsp. vegetable oil. Make 3-4 slits in sweet potato; cook in microwave until just soft. When cool enough to handle, peel, cut into chunks, and puree in a food processor.
• Step 2: Heat remaining vegetable oil in sauce pan, and sauté kale about 5 minutes. In a medium sauce pan, boil water and milk, add grits and sweet potatoes; cook 5 minutes
• Step 3: Remove from heat; stir in sautéed kale. Divide grits mixture evening among 4 soufflé dishes (or place all in casserole dish). Make 4 depressions in the grits mixture with the back of a large spoon. Carefully break one egg into each hollow. Bake uncovered for 30 minutes until eggs are cooked. Let cool 10 minutes before serving

Nutrition information per serving:

Calories: 280; Total fat: 9g; Saturated fat: 2g; Protein: 12g; Carbohydrates: 38g; Cholesterol: 185g; Dietary Fiber 4g; Sodium: 410mg

Each serving provides: An excellent source of vitamin A, vitamin C, thiamine, niacin, folate, phosphorus, and iodine, and a good source of protein, fiber, vitamin D, riboflavin, vitamin B6, vitamin B12, pantothenic acid, potassium, calcium, iron, and magnesium

References

1)       Evert, A. (2013, February 18). Vitamin a: Medlineplus medical encyclopedia. Retrieved fromhttp://www.nlm.nih.gov/medlineplus/ency/article/002400.html

2)       Goodrow EF, et al. Consumption of one egg per day increases serum lutein and zeaxanthin concentrations in older adults without altering serum lipid and lipoprotein cholesterol concentrations.JN 2006; 136(25):19-24.

3)       Higdon, J. (2007, November). Vitamin a: Micronutrient information center. Retrieved fromhttp://lpi.oregonstate.edu/infocenter/vitamins/vitaminA/index.html

4)       USDA Database of Vitamin A (mcg RAE) and Vitamin E (mg AT) for National Health and Nutrition Examination Survey 1999-2000. 2006. Beltsville, MD: Agricultural Research Service, Food Surveys Research Group.

Today’s post is from James House, Ph.D. Dr. House is studying the relationship between water soluble vitamin nutrition, the metabolism of amino acids, and how they relate to optimal growth and health of individuals. He also maintains a strong focus towards the development of functional foods of animal origin.  He is also a member of ENC’s Scientific Advisory Panel (SAP).

Folate (folic acid, vitamin B9) is a water soluble B vitamin, traditionally associated with the consumption of green, leafy vegetables.  However, since the late 1990’s, several jurisdictions, including the US and Canada, have mandated the inclusion of synthetic folic acid into enriched white flour, as well as other cereal-based foods.  The main reason for this population health initiative was to effect a reduction in the number of babies born with a neural tube defect (NTD).  Evidence is accumulating that the initiative, combined with strong campaigns to encourage folic acid supplement usage by women of child bearing age, has been effective in reducing the occurrence and recurrence of NTDs.  However, the folic acid fortification strategy is not without its concerns.  The recent surge in the demand for gluten-free foods, coupled with a demand for foods lower in refined carbohydrates, challenges the usefulness of enriched wheat flour as the fortification vehicle.

Eggs, on the other hand, are good sources of protein, naturally gluten-free, and contain little in the way of carbohydrate.  Furthermore, one large egg can supply 10% of the Daily Value for folate.  This value can be increased approximately 250%, up to 60 µg per egg, by increasing the synthetic folic acid content of the laying hen diet.  The hen converts the relatively inexpensive and synthetic form of folic acid in her diet to the more metabolically active form, called 5-methyltetrahydrofolate – this is the major circulating form of folate in the human bloodstream.  Previous research has documented that the folate found in egg is highly available (>100% relative to folic acid), in comparison to plant-based folates (generally <50%).  Therefore, folate-enriched eggs offer an additional food-based vehicle for the addition of this important water-soluble vitamin to the human food supply.  Beyond folate, other opportunities exist for egg fortification, including recent work examining the potential to enrich eggs with vitamins D and B12.

There are many reasons to consume adequate amounts of B6 in your diet. Like the rest of the B-complex vitamins, B6 is water soluble and cannot be stored by your body, so it’s important to replenish your body’s supply of the vitamin on a daily basis to reap its many health benefits, including:

• Greater supply of energy – B6 also helps the body make hemoglobin, the part of your blood that carries energy-boosting oxygen to the brain and other organs.
• Increased brain function – All of the vitamins in the B-complex family have benefits for the brain, but B6 is especially important for regulating mood and preventing mental fatigue. This water-soluble vitamin is needed for the brain to produce serotonin, a feel-good neurotransmitter that relaxes you and lifts your spirits.

The current RDAs throughout the lifespan are captured below. In general recommendations for adult men and women are 1.3 milligrams per day.

Fortunately, there are many foods that you can eat in order to make sure that your body is getting enough vitamin B6. Major sources of vitamin B6 include cereal grains, legumes, vegetables (carrots, spinach, peas, and potatoes), milk, cheese, eggs, fish, liver, meat, and flour ¹. In fact, one egg provides 0.05 mg or 3.8% DV of vitamin B6.  Add some chicken and chickpeas to the tomato and avocado egg salad recipe below for a fresh and nutritious meal brimming with B6 (and many other important nutrients) ².

Tomato & Avocado Egg Salad

Ingredients:

• 6 hard-boiled eggs, sliced
• 2 avocados, chopped
• 1 cup chopped tomato
• ½ cup chopped red onion
• ¼ cup chopped fresh parsley OR cilantro
• Spinach OR lettuce leaves
• Dressing:
  • 2 Tbsp. fat-free mayonnaise
  • 2 Tbsp. reduced-fat sour cream
  • 1 Tbsp. fresh lemon juice
  • ½ tsp. salt
  • ¼ tsp. hot pepper sauce

Directions:

• Mix dressing ingredients in small bowl
• Reserve and refrigerate 6 center slices from eggs for garnish. Chop remaining eggs
• Combine chopped eggs, avocados, tomato, onion and parsley in large bowl; toss gently to mix. Add dressing; stir gently just until ingredients are evenly coated with dressing
• Refrigerate at least 1 hour to blend flavors. Serve on spinach leaves, garnished with reserved egg slices

References:

1)      Mayo Clinic. N.p., 1 Sept. 2012. Web. 25 June 2013. <http://www.mayoclinic.com/health/vitamin-b6/NS_patient-b6>.

2)      Office of Dietary Supplements . N.p., n.d. Web. 25 June 2013. < http://ods.od.nih.gov/factsheets/VitaminB6-HealthProfessional />.

Today’s blog post is written by Nawal Al-Nouri, ENC’s Dietetic Intern. Nawal studies Nutrition and Dietetics at the University of Illinois at Chicago, and will be eligible to sit for the RD exam in December of 2013. She maintains a balanced lifestyle by staying active and exposing herself to new ideas, and enjoys cooking and experimenting with different food genres and flavors.

It may be interesting to learn that Columbus’ ships are believed to have carried the first of the chickens related to egg production in America today. It may also surprise you that eggs have several additional functions other than eating them scrambled, fried, poached, baked, in the shell, or as omelets.

Few foods are entirely as versatile as the egg. It has been stated that each of the one-hundred pleats on a chef’s toque represents a different way use eggs, and within each pleat are countless variations. Indisputably, there are other foods or products that can be used to perform similar functions as eggs in a certain setting, however no other food is known to match all properties of the egg. Below are a few unique purposes of the multi-functional egg:

Leaven- Eggs serve as a leavener to increase volume and add lightness to food due to their excellent ability to foam. Eggs, especially the whites, function to leaven soufflés, meringues, angel food cakes and more.

Emulsify- Emulsions may be oil droplets in water, such as mayonnaise or water droplets in fat, such as butter. Egg yolks are considered chemical
emulsifiers, so they have one end that dissolve in water and one dissolved in oil, which helps combine two otherwise immiscible liquids.

Bind & thicken- Eggs act as “glue” and bind ingredients in foods such as meatloaves and casseroles to keep them from crumbling, as well as thicken puddings and sauces.

Impede crystallization- If crystals in candies, frostings, or ice creams form too quickly, they will be small in number but large in size, resulting in an unpleasant grainy texture. Egg whites in particular are introduced as an interfering agent, slowing down the crystallization process to form many fine crystals, bringing about a smooth overall texture.

Color- The proteins in the eggs influence the browning reactions of foods while the alkaline nature of eggs will help improve browning of acidic products by lowering their acidity. Eggs are responsible for the rich golden glow in custards, egg noodles and béarnaise sauce.

Moisturize & Dry- The fat in the yolk of the egg helps moisturize baked goods, while the white helps give that desired crisp dryness in baked goods such as cream puffs.

The functions of egg whites, egg yolks, and whole eggs are diverse—contributing to its resourcefulness. Adding eggs to your food items provide a wide variety of nutrients, increasing the quantity of essential nutrients specifically in desserts and sauces which may otherwise not provide adequate nutrient value. Check out the American Egg Board’s Eggcyclopedia for a more in depth look at the versatility of eggs.