Plant-Based Diets: How Choline Deficiency Affects Childhood Brain Development and Alzheimer’s

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Researchers are becoming increasingly concerned that plant-based and vegan diets can lead to widespread deficiencies of dietary choline, an essential nutrient that is critical to brain health, particularly during fetal development.

Closely related to the B complex family of vitamins, choline is found in virtually all living cells where it plays a vital role in manufacturing cell membranes, maintaining and supporting metabolic functions and directing signals through the central nervous system. Choline is also required for the production and metabolization of fats and cholesterol, and aids in protecting the liver from the accumulation of excess fatty deposits.

The primary dietary sources of choline include beef, eggs, dairy products, fish, and chicken, with much lower levels found in nuts, beans, and cruciferous vegetables such as broccoli.

Choline is also produced by the human liver, but not in the amounts needed to meet the body’s requirements.

Minimum Daily Requirement
In 1998 the US Institute of Medicine recognized the importance of choline by issuing recommendations for minimum daily intakes, including 550 milligrams (mg) per day for men and 425 mg per day for women. Recommended intake levels increased to 450 mg during pregnancy and 550 mg for women who breastfeed.

These amounts don’t seem like much, considering that one hard-boiled egg contains about 113 mg of choline. But according to a National Health and Nutrition Examination Survey, 90 percent of children (but not infants), pregnant women, and adults aren’t getting enough.

Essential for Health
According to the National Institutes of Health, choline is an essential nutrient, required by the brain and nervous system to regulate functions that include memory, mood, and muscle control. Choline is also required to form the membranes that surround the body’s cells.

Although the human body produces some choline in the liver, most of what we need comes from the food we eat.

Choline is naturally found in egg yolks, fish (like salmon), meat, and dairy. The best source is eggs. One large egg can provide 25 percent of a pregnant woman’s daily choline needs and more than half the choline required for 4- to 8-year-old children.

A recently published paper in the British Medical Journal (BMJ) addresses why the move to plant-based diets has worsened this problem, placing unborn children at risk. “Choline is transported to the fetus in utero. It’s an important nutrient because it’s involved in the development of the brain and spinal cord. Shortfalls could impact the cognitive development of children after they’re born,” according to Emma Derbyshire BSc, PhD, RNutr, and author of the paper.

She emphasizes that the body doesn’t produce enough choline on its own. “The concept that the body will adapt is somewhat of a myth,” Derbyshire said. “Choline can be likened to omega-3 fatty acids in that it is an ‘essential’ nutrient that needs to be obtained from dietary or supplemental sources, as the body doesn’t produce enough to meet human requirements.”

Recent research shows that less than 9 percent of pregnant women meet the minimum daily requirement.

Dr. Praveen S. Goday, CNSC, FAAP, professor pediatric gastroenterology and nutrition at the Medical College of Wisconsin, points out that the nutrient is key not just for in utero brain development, but as a newborn becomes a toddler as well. “At the present time, the American Academy of Pediatrics has included choline among the critical nutrients that support brain growth in the first 1,000 days of a child’s life. In other words, life in utero plus the first 2 years of life,” Goday said.

He cautioned, “There is a concern that failure to provide key nutrients such as choline during this critical period of brain development may result in lifelong deficits in brain function despite subsequent nutrient repletion.”

Cholesterol and Fear of Eggs
The declining rates of choline intake are linked, in part, to concerns about cholesterol. In the 1970s, the American Heart Association recommended reducing intake of dietary cholesterol to less than 300 mg per day, and no more than three eggs per week.

This advice led to drastically reduced choline intake, since the foods people avoided to reduce cholesterol levels were also the best sources of this critical nutrient: eggs, dairy, and meat.

Today, that advice has been reversed and eggs, alongside healthy meats and some dairy products, are no longer looked as a harbinger of skyrocketing cholesterol. But many people still aren’t eating enough of these foods to get to the recommended choline intake.

Vegans and vegetarians who avoid fish and dairy products are particularly at risk. While vegetables like Brussels sprouts, broccoli, cauliflower, wheat germ, peanuts, and many varieties of beans have some choline, it’s difficult — though not impossible — to eat enough of these foods to meet the minimum daily requirement. A half a cup of broccoli, for example, has just over 31 mg of choline, barely 6% of the recommended daily intake.

“The general population should think about whether they are obtaining some of the major dietary choline providers, such as meat, milk, and eggs. If these are not being consumed, then supplementation strategies will be required,” Derbyshire said.

“This becomes particularly important at key life stages, such as pregnancy and postpartum if breastfeeding, when choline is critical to fetal and infant development,” she added.

Goday says older children can stay on a vegan diet as long as care is taken to ensure they get nutrients that might be missed if they avoid animal products. “Children and adults who are vegans need some form of supplemental vitamins, particularly vitamin B-12 and potentially others, and may also need supplemental minerals,” Goday said.
He points out that infants may be at particular risk, since choline is not a common ingredient in most infant vitamin preparations, although it is an ingredient in some pediatric and prenatal vitamins.

Choline and Alzheimer’s
Inadequate choline intake has also been associated with increased risk of a variety of health issues, especially conditions that affect the brain. Choline protects against age-related cognitive decline, and sufficient levels of choline in the brain will preserve neurons, brain size, and neural networks to prevent memory loss in aging brains.

Brain abnormalities in people with dementia and Alzheimer’s can be linked in part to choline deficiency.

A 2011 study from Boston University School of Medicine found higher choline intake was strongly associated with better cognitive function. It even prevented deterioration of the brain in senior citizens.

One reason for this is that choline is a precursor of the important neurotransmitter acetylcholine, a chemical that plays a critical role in the transmission of brain impulses between nerves, muscles and organs. In this role it is involved directly with cognition, long and short-term memory, stimulus response, and mental energy. Since acetylcholine levels increase rapidly after consuming choline, researchers have turned to choline supplements in the treatment of various disorders marked by low brain levels of acetylcholine, including Huntington’s disease, Parkinson’s disease, Alzheimer’s disease, and tardive dyskinesia.

Additionally, a class of drugs called anticholinergics that work, in part by reducing acetylcholine in the brain, are linked to an increased risk of Alzheimer’s.

Dr. James Pickett, head of research at the Alzheimer’s Society, said in a statement that choline levels are so important that drugs that negatively affect choline should be avoided for older people.

“Current guidelines for doctors say that anticholinergic drugs should be avoided for frail older people because of their impact on memory and thinking,” Pickett said. “But doctors should consider these new findings for all middle aged and older people as we continue to learn more about long-term use and the risk of dementia,” he said.

Summary
Choline is an essential nutrient vital for many bodily functions, especially brain health. According to experts up to 90 percent of Americans are choline-deficient, due in part to recommendations made by the American Heart Association in the ’70s and a general move toward plant-based diets.

Choline deficiency can have serious consequences for cognitive health, starting before birth and continuing into old age. A deficiency of choline can also lead to increased fatty deposits in the liver, memory loss, and poor muscle coordination.

Foods highest in choline include egg yolks, liver, meats, brewer’s yeast, milk, legumes and whole grain cereals. Choline can be manufactured in the human body with the help of vitamin Bl2, folic acid, and the amino acid methionine. Choline is also available as a dietary supplement in a variety of forms, including phosphatidyl choline, choline chloride, and choline bitartrate. Choline supplements should be avoided by persons who suffer from manic depression, as they may deepen the depressive phase of this disorder.

Source: Emma Derbyshire. BMJ Nutrition, Prevention & Health, 2019; bmjnph-2019-000037 DOI: 10.1136/bmjnph-2019-000037

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