Natural treatments for memory and mental function impairment

• PRINCIPAL PROPOSED NATURAL TREATMENTS: Bacopa monniera (brahmi), ginkgo, ginseng, phosphatidylserine
• OTHER PROPOSED NATURAL TREATMENTS: Carnitine, cranberry, creatine, dehydroepiandrosterone, folate, guarana, huperzine A, isoflavones, lobelia, muira puama, multivitamin-multimineral supplements, neuropeptides, Rhodiola rosea, ribose, rosemary, saffron, Spanish sage, tyrosine, vinpocetine, whey protein, vitamin B₁, vitamin B₁₂, vitamin E, zinc

DEFINITION: Treatment of impaired memory and cognitive function.

Introduction

Mental function often declines with age, particularly under conditions of stress or fatigue. Most people over forty experience some memory loss, known as age-related cognitive decline or age-associated memory impairment. This experience occurs for several age-related reasons, including decreased blood flow to the brain, shrinking of the brain's hippocampus, which is responsible for memory, a vitamin B₁₂ deficiency, or the onset of a neurocognitive disease like Alzheimer's or vascular dementia. A few natural treatments might help delay or prevent some of these occurrences.

Principal Proposed Natural Treatments

Statistically, it is easier to demonstrate a significant improvement than a small one. For that reason, it is more difficult to prove the effectiveness of a treatment in a mild condition than in a severe one. Because of this, far more evidence supports the use of natural supplements for treating Alzheimer’s disease than for improving mental function in healthy people. Nonetheless, there is some evidence for the latter.

Ginkgo biloba. An extract made from one of the oldest living tree species, Ginkgo biloba, is a commonly recommended natural treatment for cognitive decline and age-related memory issues, as well as a natural aid for individuals with Alzheimer’s disease and a preventative measure for healthy older adults. The plant's extract is rich in antioxidant and anti-inflammatory properties. Ginkgo may also help improve natural, age-related memory loss and enhance mental function in younger people. However, research on ginkgo’s use in supporting memory and cognitive function is mixed.

Age-related mental decline. In six of nine double-blind studies, using Ginkgo biloba extracts significantly improved age-related cognitive degeneration compared with the placebo. For example, in a double-blind, placebo-controlled trial, 241 older adults with mildly impaired memory received a placebo or ginkgo for twenty-four weeks. The results showed that ginkgo produced modest improvements in certain types of memory. Another double-blind, placebo-controlled trial examined the effects of ginkgo extract in forty healthy men and women aged fifty-five to eighty-six years. In six weeks, the results showed improvements in measurements of mental function. Four other trials also showed benefits, involving about 135 participants.

Set against these positive findings is a large twenty-four-week study with 214 participants that found no benefit in ordinary age-related memory loss. It has been suggested that flaws in the trial’s design led to this negative outcome. However, three other studies involving about four hundred people also failed to find significant benefit with daily ginkgo use. Another double-blind, placebo-controlled study used a one-time dose of ginkgo and found no benefits. Also, a small, double-blind, placebo-controlled study looking for immediate mind-stimulating effects did not find them.

A large study sponsored by the Institutes of Health and the large-scale, longitudinal Ginkgo Evaluation and Memory (GEM) Study found no benefit of ginkgo in memory-related problems. The well-constructed GEM study enrolled 3,000 individuals over seventy-five and followed them for six years. Half of the participants received a placebo, while the other half received 120 milligrams of ginkgo biloba extract twice daily. No statistically significant differences were found between the groups in terms of age-related memory impairment or the risk of developing neurocognitive disorders. Conversely, a review of fourteen twenty-first-century studies on ginkgo’s impact on memory and cognition found positive results from ginkgo improving cerebral blood flow supply, concentration, insulin levels, body mass index, inflammation, and more.

Besides negative trial results, other weaknesses exist in the literature. There is a lack of standardization across studies in the function or type of memory measured and how memory is measured, making it difficult to compare studies and properly evaluate findings. For example, in one positive study, ginkgo may speed up the ability to memorize letters but not expand the number of letters that can be retained. In another positive study, the reverse may be true. This inconsistency decreases the reliability of study results and implies that positive results may not be reproducible, eliminating their value. Ginkgo may help normal age-related memory loss, but more research is necessary to determine whether this is true.

Improving memory and mental function in younger people. Several studies enrolling about 250 people have examined the effects of ginkgo on memory and mental function in younger people. However, the benefits seen in the positive trials were inconsistent, and the largest study failed to find any effect. One study hints that benefits may occur initially and then decline after several weeks.

Several double-blind, placebo-controlled studies evaluated combined treatment with ginseng and ginkgo, or vinpocetine and ginkgo, for enhancing mental function in young people, and most found some evidence of benefit. Weak evidence suggests that combining phosphatidylserine with ginkgo might increase its efficacy. However, in two studies, ginkgo combined with the Ayurvedic herb brahmi failed to improve mental function.

Phosphatidylserine. Like ginkgo, the supplement phosphatidylserine (PS) is widely used in Europe to treat various forms of dementia. There is some evidence that PS can also help people with ordinary age-related memory loss.

In one double-blind study that enrolled 149 people with memory lossbut not dementiaPS provided significant benefits compared with the placebo. Persons with the most severe memory loss showed the most improvement.

Another double-blind trial of 120 older people with memory complaintsbut not dementiafound no benefits. This discrepancy may have to do with the type of PS used (the second trial used the more modern soy-derived supplement). Phosphatidylserine might enhance the effectiveness of ginkgo.

Ginseng. Several studies have found indications that the herb ginseng might enhance mental function. However, the specific benefits seen have varied considerably from trial to trial, tending to make the actual cognitive effects of ginseng, if any, difficult to discern.

For example, results showed that ginseng improved abstract thinking ability in a two-month, double-blind, placebo-controlled study of 112 healthy middle-aged adults given either ginseng or a placebo. However, the two groups had no significant change in reaction time, memory, concentration, or overall subjective experience.

Another double-blind, placebo-controlled study of fifty men found that eight-week treatment with a ginseng extract improved the ability to complete a detail-oriented editing task. A double-blind trial of sixteen healthy males found favorable changes in the ability to perform mental arithmetic in those given ginseng for twelve weeks.

More comprehensive benefits were seen in a double-blind, placebo-controlled trial of sixty older adults given fifty or one hundred days of treatment. The results showed that Panax ginseng produced improvements in numerous measures of mental function, including memory, attention, concentration, and ability to cope. Benefits were still evident at the fifty-day follow-up. However, virtually no improvement was seen in the placebo group, a highly unusual result that raises doubts about the study's accuracy. Finally, four double-blind, placebo-controlled studies evaluated combined treatment with ginseng and ginkgo and found inconsistent evidence of improved mental function.

Bacopa monniera (brahmi). The Ayurvedic herb Bacopa monniera (brahmi) has a traditional reputation for improving memory. However, a twelve-week, double-blind, placebo-controlled trial of seventy-six persons that tested the potential memory-enhancing benefits of brahmi generally failed to find much evidence of benefit. The only significant improvement seen among all the many measures used was one that evaluated the retention of new information. A randomized trial involving forty-eight healthy older adults found some memory-enhancing effects of B. monniera compared with placebo, but the outcomes measured were too numerous to be convincing.

In another double-blind, placebo-controlled study of thirty-eight persons, short-term use of brahmi failed to produce any measurable improvements in memory, while in a third double-blind, placebo-controlled study, using brahmi over two weeks did have some benefits, but in quite a different pattern. Finally, a study found that one-time combined treatment with ginkgo (120 milligrams [mg]) and brahmi (300 mg) failed to improve mental function.

Slightly more promising results have been seen in studies of a proprietary Ayurvedic mixture containing brahmi and about thirty other ingredients. However, these studies were generally not up to modern scientific standards.

Omega-3 fatty acids. Some research indicates that omega-3 fatty acids contribute to brain health. Omega-3s are polyunsaturated fatty acids that have been linked to lower cholesterol, blood pressure, and stroke risk. Consuming ample omega-3s, like docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), in food sources or using supplements may improve cognitive function. Some positive findings include slowing cognitive decline, lowering the risk of dementia, increasing blood flow to the brain, and renewed processing speed. In animal studies, omega-3 consumption improved cognitive function so significantly that the mice treated with omega-3 finished a maze in half the time it took the placebo group. Individuals who are omega-3 deficient have been found to have lower brain volumes than individuals without a deficiency.

Other Proposed Natural Treatments

On the basis of one small double-blind study, a proprietary mixture of substances called neuropeptides has been extensively marketed for improving mental function. Advertisements state that this product has been shown to bring about “a reversal of ten years of short-term memory decline.” However, this claim is not founded on reliable evidence. Another single study suggests that the supplement nicotinamide adenine dinucleotide might help improve temporary mental impairment caused by jet lag.

Evidence conflicts on whether multivitamin-multimineral tablets may improve cognitive function in people of various age groups. In general, the best-designed studies have failed to find benefit. However, multivitamin-multimineral supplements are helpful for people with vitamin or mineral deficiencies.

Studies of isoflavone-rich soy or red clover for enhancing mental function in women have found little to no beneficial effects.

Huperzine A is a potent chemical derived from a particular type of club moss (Huperzia serrata). This substance is really more a drug than an herb, but it is sold over the counter as a dietary supplement for memory loss and mental impairment. Some evidence indicates that it may be helpful for Alzheimer’s disease and related conditions. Very weak evidence suggests benefit for healthy people. Much the same can be said about the substance vinpocetine.

Creatine, best known for its use as a sports-performance enhancer, may improve mental function in sleep-deprived, but not necessarily well-rested, young persons. Sage and vitamin B₁₇ have slight supporting evidence from preliminary double-blind trials.

Mild vitamin B₁₂ deficiency may impair mental function. Because such deficiency is relatively common in older adults, it has been suggested that vitamin B₁₂ supplements may be appropriate in this age group. However, in the two studies that tried it, no benefits were seen.

Older adults are also commonly deficient in vitamin B₆, but a review of the literature failed to find meaningful evidence that vitamin B₆ offers any benefits. One study failed to find folate helpful either. However, in another study, folate supplementation improved mental function in older persons with high levels of homocysteine. Combinations of B vitamins, including B₁₂, B₆, and folate, have proved ineffective. In an early 2020s meta-analysis, researchers found that, overall, vitamin B is a low-risk preventative measure that can be taken to prevent or delay memory and cognition problems as individuals age.

One study failed to find any benefit with zinc. Other preliminary double-blind trials suggest that the amino acid tyrosine may improve memory and mental function under conditions of sleep deprivation or other forms of stress. Other double-blind trials suggest that a proprietary extract of the herb Rhodiola rosacea may offer a similar benefit.

Whey protein contains alpha-lactalbumin, a protein that, in turn, contains high levels of the amino acid tryptophan. Tryptophan is the body’s precursor for serotonin and is thought to affect mental function. In a small double-blind study, the use of alpha-lactalbumin in the evening improved morning alertness, perhaps by enhancing sleep quality. Another small double-blind study found weak evidence that alpha-lactalbumin improved mental function in people sensitive to stress. A third study failed to find that alpha-lactalbumin significantly improved memory in women experiencing premenstrual symptoms.

Herbs that contain caffeine would be expected to enhance mental function in healthy people, at least temporarily. These herbs include green tea, black tea, maté, and guarana. For example, in a double-blind, placebo-controlled study of 129 healthy young adults, the one-time use of guarana plus vitamins and minerals improved mental function and reduced mental fatigue among those undergoing a battery of cognitive tests. In another double-blind, placebo-controlled study, using guarana alone or guarana plus ginseng appeared to improve mental function. However, these studies had some design problems. In two other studies, no benefits were seen.

Some reports suggested that declining levels of the hormone dehydroepiandrosterone (DHEA) cause impaired mental function in older adults. On this basis, DHEA has been promoted as a brain-boosting supplement. However, large studies have failed to find any correlation between DHEA levels and mental function, and there is no direct evidence that DHEA supplements benefit older adults. One study found potential benefits for younger people.

Weak evidence from a large, double-blind, placebo-controlled study hints that using beta-carotene over many years might enhance mental function. However, long-term use of beta-carotene might present safety risks.

Other herbs and supplements proposed for enhancing memory and mental function but lack meaningful supporting evidence include gotu kola, rosemary, saffron, muira puama, sage, and lobelia. In one small double-blind study, the supplement ribose failed to prove effective in enhancing mental function, though this may have been due to the small 2-gram dose used. Also, women who are marginally deficient in iron may experience improved mental function when they correct this deficiency. Carnitine has shown some benefits in reducing mental fatigue and enhancing cognitive function in centenarians.

A large study failed to find that vitamin E helped maintain healthy mental function in women older than sixty-five years old. Further research indicates that individuals who consume plenty of foods containing vitamin E have a lower risk of early cognitive decline.

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