Nutrients In Eggs

Eggs are a nutrient goldmine!

One large egg has varying amounts of 13 essential vitamins and minerals, high-quality protein, all for 70 calories.

While egg whites contain some of the eggs’ high-quality protein, riboflavin and selenium, the majority of an egg’s nutrient package is found in the yolk. Nutrients such as:

  • Vitamin D, critical for bone health and immune function. Eggs are one of the only foods that naturally contain vitamin D.
  • Choline, essential for normal functioning of all cells, but particularly important during pregnancy to support healthy brain development of the fetus.
  • Lutein and zeaxanthin, antioxidants that are believed to reduce the risk of developing cataracts and slow the progression of age-related macular degeneration, a disease that develops with age.

PROTEIN FOODS FROM A VARIETY OF SOURCES CONTRIBUTE TO NUTRIENT ADEQUACY

Featured article in the Fall 2019 Issue of Nutrition Close-Up; written by Mickey Rubin, PhD

There has been considerable debate recently around the topic of protein quality, particularly regarding the best way to measure protein quality1 as well as the relative importance of dietary protein quality as it relates to important health outcomes, such as muscle loss with aging.2 While this discussion is important and will no doubt continue as research in this area evolves and new measures for protein quality are developed,3 less attention is often given to the important contribution of protein foods to overall nutrient adequacy. Commonly consumed protein foods contribute to nutrient intake, diet quality, and nutrient adequacy, independent from their contributions to total protein intake.4

Strategies for Protecting Children’s Eye Health

By Jessica Ivey, RDN, LDN

The Egg Nutrition Center partnered with Jessica Ivey, RDN, LDN to write this blog post. Jessica’s opinions are her own.

August is Children’s Eye Health and Safety Month. As the kids head back to school this fall, they’ll likely be spending more time looking at books and/or screens. Did you know that spending long periods of time reading, writing, watching videos, or other “near work” can create eye strain? There are several things you can do to help protect your child’s eyes.

Remember the 20-20-20 rule.

You blink less when looking at a screen, whether it be a computer, e-reader or television, which can lead to digital eye strain and dry eye. Take a 20 second break and look about 20 feet away once every 20 minutes. You can use a timer on digital devices to remind your child to take a break.

Get outside.

Studies have shown that spending time outside may lower the risk of nearsightedness in children and teens.1 More research is needed to determine whether this benefit comes from exposure to daylight or exercising distance vision. Be sure that children and adults alike wear UV-blocking sunglasses to protect their eyes from long-term UV damage. 

Eat your eggs.

One of the best ways to promote eye health is to eat a nutritious, balanced diet. Eggs are a source of lutein and zeaxanthin (252 mcg per large egg), two carotenoids important for eye health. Exposure to too much blue light may cause damage to the eye2 and these carotenoids block blue light from sunlight and digital devices, helping to protect the eyes. There are also long-term benefits as higher intake of lutein and zeaxanthin is associated with a reduced risk of advanced age-related macular degeneration.3 Lutein and zeaxanthin are also found in several vegetables, including spinach, Brussels sprouts, green peas, broccoli, summer squash, and corn, but because lutein is fat-soluble, your body is better able to absorb and use the lutein found in eggs thanks to the fat found in the yolks.

Try these nutrient-rich recipes featuring eggs.

Jessica Ivey, RDN, LDN, is a dietitian and chef with a passion for teaching people to eat healthy for a happy and delicious life. Jessica offers approachable healthy living tips, from fast recipes to meal prep guides and ways to enjoy exercise on her website, JessicaIveyRDN.com. Follow her on Facebook and Instagram.

References

  1. Sherwin JC, Reacher MH, Keogh RH, Khawaja AP, Mackey DA, Foster PJ. The association between time spent outdoors and myopia in children and adolescents. Ophthalmology. 2012;119(10):2141–2151.
  2. Scientific Committee on Emerging and Newly Identified Health Risks (SCENIHR). 2012. Health Effects of Artificial Light (https://ec.europa.eu/health/scientific_committees/emerging/docs/scenihr_o_035.pdf)
  3. Johnson EJ. Role of lutein and zeaxanthin in visual and cognitive function throughout the lifespan. Nutr. Rev. 214;72(9):605-12.

Macular Pigment Links to Eye and Brain Health

By: Jen Houchins, PhD

The dietary carotenoids lutein and zeaxanthin (yellow pigments) selectively accumulate in the retina of the eye and can be measured non-invasively with a test easily conducted outside the clinic.  The result of this short visual assessment is reported as Macular Pigment Optical Density (MPOD), which can range from 0 to values over 1 log unit, with an average around ~0.35.1  MPOD measures the amount of lutein + zeaxanthin in the retina.  Since these carotenoids cannot be synthesized by the human body, MPOD is a direct reflection of the habitual diet.  Emerging science continues to link MPOD to eye and brain health across the lifespan, which is eggciting news for egg fans, as eggs are a bioavailable food source of lutein.

The accumulation of lutein in the fovea of the retina supports eye health likely though its’ ability to act as an antioxidant and anti-inflammatory agent, capacity to absorb damaging blue light (short wavelengths), and potentially by enhancing communication among neurons.  As summarized in a recent presentation and new review paper, macular pigment is linked to visual function and is associated with reduced risk of age-related macular degeneration (AMD).  MPOD been studied in relation to speed of visual processing, contrast sensitivity, the ability to recover visibility after a bright flash of light, and various other measures of visual function.  The totality of the literature supports that dietary lutein is important for eye health across the lifespan. 1

Recent data also demonstrate that macular pigment is related to brain lutein levels, allowing MPOD to be used as a non-invasive biomarker in studies studying cognitive outcomes. 2,3  As previously shared, emerging data link MPOD to measures of math and written comprehension in preadolescent children and various studies connect lutein status to indicators of cognitive function in older adults.  Overall, macular pigment appears to be a reliable biomarker of brain lutein concentration across the lifespan, and is potentially valuable for assessment of cognition. 1,4

Most Americans do not consume an adequate amount of lutein + zeaxanthin to increase MPOD, with an average intake ~1-2 mg/day, below the suggested 6 mg/day to maintain eye health. 5  However, the good news is that increasing dietary lutein through foods and/or supplements can increase MPOD in most people. 1, 6  Lutein can be found in a variety of foods, including green leafy and other vegetables such as broccoli, brussels sprouts, and avocados.  A large egg provides 252 mcg lutein + zeaxanthin in a highly bioavailable form and egg consumption may help build macular pigment.  One study in women between the ages of 24-59 found that eating 6 eggs/week increased MPOD over a 12-week period, with a larger increase observed in participants with lower baseline MPOD levels. 6

So regardless of your age, current research indicates that a habitual diet that includes various food sources of lutein can help support eye and brain health.  Please explore our recipes to find new ways to prepare and eat eggs!

 

References

  1. Stringham, J.M., E.J. Johnson, and B.R. HAmmond, Lutein Across the Lifespan: from Childhood Cognitive Performance to the Aging Eye and Brain. Curr Dev Nutr, 2019.
  2. Vishwanathan, R., W. Schalch, and E.J. Johnson, Macular pigment carotenoids in the retina and occipital cortex are related in humans. Nutr Neurosci, 2016. 19(3): p. 95-101.
  3. Vishwanathan, R., et al., Macular lutein and zeaxanthin are related to brain lutein and zeaxanthin in primates. Nutr Neurosci, 2013. 16(1): p. 21-9.
  4. Wallace, T.C., A Comprehensive Review of Eggs, Choline, and Lutein on Cognition Across the Life-span. J Am Coll Nutr, 2018. 37(4): p. 269-285.
  5. Johnson, E.J., et al., Intake of lutein and zeaxanthin differ with age, sex, and ethnicity. J Am Diet Assoc, 2010. 110(9): p. 1357-62.
  6. Wenzel, A.J., et al., A 12-wk egg intervention increases serum zeaxanthin and macular pigment optical density in women. J Nutr, 2006. 136(10): p. 2568-73.

What are the nutritional differences for different types of eggs?

There are some common misconceptions about the nutritional value of different types of eggs. For example, some people have the impression that brown eggs are nutritionally superior to white eggs, or that cage-free or free-range eggs are nutritionally superior to conventional eggs. In reality, none of these is true unless the hens’ diets have been altered.

Brown eggs come from hens with brown feathers and brown earlobes, and white eggs come from hens with white feathers and white earlobes, but the nutritional composition of those eggs is the same. Similarly, label claims such as “Cage-Free,” “Pasture-Raised,” “Enriched Colony,” “Free-Range,” “Conventional” and even “Organic” simply refer to the way the eggs were farmed and unless the feed is fortified (see below), do not denote meaningful nutritional differences.

The cost of one type of egg relative to another type of egg is also not an indicator of nutritional value; it is a reflection of the farming method used to produce the egg (or in the case of brown eggs, it is because the birds are slightly larger and require more food).

Yolk color is dependent on the hen’s diet, and specifically, carotenoid intake.  Carotenoids are color pigments that give egg yolks their yellow-orange hue.  Hen feed (regardless of the farming method) can be enhanced with carotenoids via carotenoid-rich extracts such as marigold which can lead to a darker yolk.

The only way to produce eggs with higher levels of nutrients is by feeding the hens that lay the eggs a diet of nutritionally fortified feed. In such cases, the eggs are marketed as nutrient- or nutritionally enhanced, and their packaging will specify nutrient content. For example, certain eggs may be enriched with omega-3 fatty acids or higher levels of vitamin D. When in doubt, always check the Nutrition Facts label on the carton.

Different types of eggs are available in order to accommodate people’s preferences and budgets. But at the end of the day, from a nutrition perspective, all eggs are nutrient-rich and can be part of healthy dietary patterns. And, unless they have been nutritionally enhanced, all eggs have the same essential nutrients— regardless of the shell color of the egg or the way the egg was farmed.

Please see the Egg Nutrition Center’s labeling handout for more details, and other common terms on egg cartons.  Regardless of the hen’s diet or farming method, egg farmers are committed to providing high-quality eggs, making the health and well-being of their hens top-priority, and continue to be dedicated to supporting sustainable eating patterns.

Choline – The Underconsumed and Underappreciated Essential Nutrient

Featured article in the Winter 2019 Issue of Nutrition Close-Up; written by Taylor C. Wallace, PhD, CFS, FACN

“Recognition of the growing evidence relating inadequate intakes to health consequences coupled with evidence of suboptimal intakes in high-risk populations, warrants a need for improved public health recommendations for choline” was the consensus of more than 40 experts attending the 2018 Choline Science Summit, whose findings were summarized recently in a feature article in the journal Nutrition Today.1