Research News: Choline, Lutein, and Cognition

Featured article in the Spring 2019 Issue of Nutrition Close-Up; written by Maggie Moon, MS, RD

Health is not just the absence of disease, but the presence of optimal wellness. Though nutritional guidance historically focused on preventing deficiency and toxicity from nutrients, today there is a growing interest in leveraging nutrients to improve the “healthspan,” or years of life in good health.

Time is of the essence to apply this to neuronutrition. According to the Alzheimer’s Association, the number of Americans living with Alzheimer’s dementia is expected to more than double by 2050 from today’s 5.7 million to nearly 14 million.1 Worldwide, today’s 50 million people with dementia will more than triple by 2050, according to the World Health Organization.2
Lutein and choline are among the most underconsumed and underappreciated nutrients emerging into the spotlight for brain health and cognition. Recent research highlights their potential
for preventing and improving cognitive decline.

Choline: For the Kids
According to 2013-14 NHANES data, U.S. adults are falling short on the recommended 550 mg/d choline: men average 402 mg/d and women average 278 mg/d.3 (Table 1) Choline is a de facto
essential nutrient because the small amount produced by the liver is not enough to meet the body’s needs, which includes the use of choline in regulating memory. New research suggests the
benefits of choline intake can be passed down two generations.

In exciting, first-of-its-kind animal research published in early 2019, when female animals consumed 5 mg/kg of choline during pregnancy and lactation, their offspring had fewer risk factors for Alzheimer’s disease, including reduced beta-amyloid accumulation, homocysteine, and pro-inflammatory gene expression.5 The study looked at two generations. The first generation only had exposure to choline in utero and during breastfeeding. They showed fewer cognitive deficits in old age compared to peers without any exposure to choline. What’s more, the second generation also enjoyed cognitive benefits.

The researchers found brain homocysteine levels went down in both generations, as did expression of 27 genes, including those that promote inflammation. While these findings are encouraging, the results need to be confirmed in well-designed human trials. Recent research in humans has shown that maternal choline intake benefits at least one generation. Caudill and colleagues tested 930 mg/d choline in the maternal diet during the third trimester, which resulted in improved infant information processing speed, aka reaction time, compared to the group with maternal intake at recommended levels (480 mg/d).6 Even in the 480 mg/d group, the infants with the longest exposure performed significantly better. Therefore, there seem to be benefits of increasing choline intake beyond current recommended levels and starting early.

TABLE 1: CHOLINE mg/d

Source: Institute of Medicine. Dietary reference intakes for vitamin C, vitamin E, selenium, and carotenoids. Washington, DC: The National Academies Press; 2000.

Seeing Lutein’s Impact on Brain Health through Novel Measures

Dietary Reference Intakes for lutein do not currently exist, though there is strong interest and rationale for developing them.7 Americans average 1-2 mg/d of lutein. For now, the best estimate we have from the body of scientific literature is that 6 mg/d may be an effective level of lutein to reduce the risk of age related macular degeneration (AMD). The evidence suggests that lutein is likely safe at long-term doses up to 20 mg/d. (Table 2) Long-term studies demonstrating the safety of doses are needed, though the daily intake from average food intake is generally safe.

Lutein accumulates in the human brain, and its neuroprotective role may be due to antioxidant activity, anti-inflammatory properties, and its role in stabilizing cell membranes. A 2019 randomized controlled trial examined the effects of lutein on brain function in a small group of older white men.8 After a year of taking 10 mg/d lutein, researchers found significantly increased brain connectivity. What was surprising is that rather than restoring “youth-like” brain activity, the older brains seemed to show enhanced connections between networks that are separated earlier in life. Their brains weren’t turning back the clock, they were just making better use of what they had.

TABLE 2: LUTEIN mg/d

Source: Ranard KM, et al. Dietary guidance for lutein: consideration for intake recommendations is scientifically supported. Eur J Nutr. 2017;56s:37-42. (Journal article) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5715043/

A late-2018 study in a small group of older adults found that better lutein status was associated with stronger white matter integrity in the brain.9White matter refers to the white myelin sheath protecting neurons and information transfer speed. This study’s findings adds to prior studies linking better lutein status to improved white matter integrity in areas of the brain that commonly experience age-related decline.

These new research studies add to our understanding of how lutein improves brain health.

Putting it on the Plate
Like we say in the trade, it’s not nutrition until you eat it. When thinking about putting choline and lutein on the plate, consider what’s realistic and can easily be made into delicious, nutritionally-balanced meals and snacks. For a look at the choline and lutein content in accessible, convenient, brain-boosting foods, check out Table 3. You’ll notice that some foods are strong in choline, others in lutein. Eggs are one of the only foods that provide both choline and lutein. All the foods fit into a diet for optimal brain health. More recently, it’s been shown that intermittent
fasting may help slow aging and extend lifespan. Studies conducted in mice show that fasted rodents live much longer than rodents who ate freely every day.⁵ These findings are complementary to human studies which show that fasting lowers several biomarkers for aging and cancer, which can help prolong lifespan.6 In a very recent study conducted
at Harvard University,7 fasting was shown to help keep certain cell components in a “youthful” state, which may in turn improve life expectancy.

TABLE 3