Filetype PDF | Posted on 08 Jan 2023 | 4 years ago
Authentication
digital resources
110x Filetype PDF File size 0.52 MB Source: www.thelancet.com
Review
The EAT–Lancet reference diet and cognitive function across
the life course
Boushra Dalile*, Curie Kim*, Andy Challinor, Lucie Geurts, Eileen R Gibney, Marcelo V Galdos, Giorgio La Fata, Sophie Layé, John C Mathers,
David Vauzour, J Martin Verkuyl, Sandrine Thuret
The EAT–Lancet Commission devised a sustainable reference diet with the aim of reducing the incidence of non- Lancet Planet Health 2022;
communicable diseases and mortality globally while improving food system sustainability. The extent to which the 6: e749–59
reference diet supports cognitive function across the life course, however, has not yet been evaluated. This Review *Contributed equally
assesses the evidence for diet supporting cognitive function from childhood into old age. A comprehensive but Translational Research Center
non-exhaustive literature search was done, synthesising studies that investigated the effect of whole foods on cognition for Gastrointestinal Disorders,
in healthy, community-dwelling human participants. We found that the current evidence base is weak with mixed Department of Chronic
Diseases and Metabolism,
conclusions and multiple methodological caveats, which precludes strong conclusions pertaining to the suitability of KU Leuven, Leuven, Belgium
dietary recommendations for each food group per age group. Long-term intervention and prospective cohort studies (B Dalile PhD); Department of
are needed to reduce this knowledge deficit. Revising dietary recommendations with the aim of maintaining an Basic and Clinical Neuroscience,
adequate nutrient intake to sustain healthy cognitive function across the life course could be worthwhile. This Review Institute of Psychiatry,
Psychology and Neuroscience,
outlines recommendations for future work to help improve the current knowledge deficit regarding dietary intake and King’s College London, London,
cognitive function across the life course and its implications for dietary guidelines such as the EAT–Lancet Commission. UK (C Kim PhD, S Thuret PhD);
Institute for Climate and
Introduction The trajectory of cognitive decline is established by a Atmospheric Science, School of
Earth and Environment,
In January, 2019, the EAT–Lancet Commission described a complex interplay of genetic and environmental factors, University of Leeds, Leeds, UK
universal, healthy reference diet to realign global food including early life exposure to cognitive activities, (Prof A Challinor PhD,
systems, improve environmental sustainability, and socioeconomic status, and education. Nutrition has M V Galdos PhD); International
1 Life Sciences Institute
nurture human health. The reference diet is based on attracted substantial attention as a modifiable environ- European Branch, Brussels,
global scientific targets, derived from the best available mental factor due to its potential ability to reduce the risk Belgium (L Geurts PhD);
evidence for healthy diets and sustainable food production, of age-related cognitive pathologies through the myriad Institute of Food Health,
and allows the global food system to operate within safe of nutrients and food ingredients that might benefit School of Agriculture and Food
boundaries to help achieve the UN Sustainable 4 Science, University College
cognitive function. Dublin, Dublin, Ireland
Development Goals and the Paris Agreement. The diet is The creation of the reference diet relied on available (Prof E R Gibney PhD); Health
largely plant-based, consisting of whole grains, fruits, evidence pertaining to non-communicable diseases, Nutrition and Care Innovation,
vegetables, nuts, legumes, unsaturated oils, low to focusing mainly on cardiometabolic health, cancer risk, Global Research and
moderate amounts of seafood and poultry, and no or low and mortality. In this Review, we provide a non-exhaustive Development Center,
DSM Nutritional Products,
red meat, processed meat, added sugar, refined grains, narrative overview of the current evidence base to further Kaiseraugst, Switzerland
and starchy vegetables. For most people, the reference diet evaluate whether the EAT–Lancet reference diet is (G La Fata PhD); Nutrition et
requires a substantial dietary shift. Specifically, it requires appropriate for maintaining healthy cognitive function Neurobiologie Intégrée,
a global increase of more than 100% in consumption of across the life course. A major challenge in establishing INRA Bordeaux University,
Bordeaux, France (S Layé PhD);
healthy foods and a more than 50% reduction in dietary strategies to improve human health is that Human Nutrition Research
consumption of foods that are not as healthy as other nutritional requirements and the effect of dietary Centre, Population Health
foods. The Commission acknowledges the need to modification on cognitive function can vary throughout Sciences Institute, Newcastle
University,
implement these changes differently depending on the different life stages.5 Therefore, we assessed available Newcastle Upon Tyne, UK
region, and proposed that shifting from current unhealthy evidence across the life course (from children aged (Prof J C Mathers PhD); Norwich
dietary patterns to the EAT–Lancet reference diet could 2 years to older adults) and restricted our analysis to Medical School, Biomedical
prevent 10·8–11·6 million (19·0–23·6%) deaths per year healthy community-dwelling individuals to match the Research Centre, University of
East Anglia, Norwich, UK
globally by reducing the incidence of diet-related obesity approach of the Commission.1 (D Vazour PhD); Danone
and non-communicable diseases, such as cardiovascular Nutricia Research, Nutricia
1 Advanced Medical Nutrition,
disease, cancer, and diabetes. Whole grains Utrecht, Netherlands
The Commission proposed that a healthy diet should Whole grain consumption during childhood and (J M Verkuyl PhD)
not only promote the absence of disease, but also adolescence seems to variably affect different cognitive Correspondence to:
1
optimise physical, mental, and social wellbeing. Optimal domains. In a longitudinal study in young children, diet Dr Sandrine Thuret, Department
cognitive function, broadly defined as the ability to learn, scores indicated that whole grain consumption was not of Basic and Clinical
6 Neuroscience, Institute of
remember, and deploy attention, is essential to mental associated with cognitive outcomes at age 10 years. Psychiatry, Psychology and
wellbeing and functioning in daily life. In typical However, consumption of 360 g per day of a mixed-grain Neuroscience, King’s College
conditions, a slow process of neural atrophy that affects product during a 9-week period protected against the London, London SE5 9RT, UK
cognitive function begins around 30 years of age.2 effects of mental fatigue induction on attention, vigilance, sandrine.1.thuret@kcl.ac.uk
Furthermore, increased cognitive decline has been and response impulsivity in adolescents.7 Mixed-grain
prospectively associated with increased risk of death.3 products could also mitigate the adverse effects of white
www.thelancet.com/planetary-health Vol 6 September 2022 e749
Review
8 fruits and vegetables with high β-carotene were negatively
rice on attention and impulsivity. Other cognitive
domains, such as visual perception and visuospatial correlated with executive function.18
reasoning, are improved when children consume more The beneficial effect of fruit and vegetable consumption
9
than 46 g per day of high-fibre grain products. There are on cognitive health is more evident in older adults. Older
no studies on the effects of whole grain consumption on participants showed low error rates on a verbal learning
cognition in adults. test after 90 days of consuming 12 g of freeze-dried
The relationship between whole grains and cognitive blueberry, blended into a powder compared with
19
function in older populations is weak. Consumption of placebo. Similarly, high consumption of fruits and
rye bread during a 3-day period showed no significant vegetables has been associated with a 26% reduction in
effects on cognitive performance compared with 20
risk of cognitive disorders. Furthermore, differences in
consumption of white wheat-based bread. However, cognitive function equivalent to 3·5 years of age between
cardiometabolic health markers, such as postprandial the lowest and highest quintile of total vegetable
insulin response and glucose tolerance, were improved consumption have been reported, with individuals in the
after rye bread consumption and were correlated with lowest quintile being twice as likely to show cognitive
improved working memory and selective attention.10 decline than individuals in the highest quintile.21
Improved cardiometabolic health has a positive effect on Compared with fruit, consumption of vegetables could
cognitive function,11,12
suggesting that cognitive perfor- be more beneficial in old age. The Chicago Health and
22
mance in older adults could be maintained by whole Aging Project (CHAP) cohort showed no association
grain consumption. Furthermore, a positive correlation between combined fruit and vegetable intake and
was found in women older than 60 years, in whom intake cognitive change during a period of 6 years. However,
of whole grain cereal was associated with improved high vegetable intake alone was significantly associated
cognitive function assessed by the Mini Mental State with slow cognitive decline, with a further 35% reduction
Examination (MMSE)—a measure of global cognitive in the annual rate of cognitive decline in the fourth
function and a screening tool for cognitive impairment, quintile of vegetable consumption versus the first.
executive function, memory, and attention.13 Individuals who consumed two or more servings of
vegetables per day exhibited the equivalent cognitive age
Tubers or starchy vegetables of individuals who were 5 years younger.23 Green leafy
There are few studies of the effects of tubers and starchy vegetables had the strongest association with cognitive
vegetables on cognitive function. Improved verbal function, which was also shown in a separate population
declarative memory was found in children after in which individuals consuming one or two servings of
consumption of 50 g of deep-fried potatoes compared green leafy vegetables per day had cognitive performance
with consumption of 50 g of mashed potatoes and 50 g of equivalent to being 11 years younger than individuals
white rice.14 who rarely or never consumed them.24
Older adults with poorer memory at baseline Based on the
showed improvement in verbal declarative memory current evidence, fruits and vegetables, although
independent of plasma glucose concentration after generally bene ficial for cognitive functioning, could have
consumption of carbohydrate sources compared with differential effects on specific cognitive domains across
15
control individuals. However, as this evidence is from the life course; these differential effects require further
studies with small samples sizes, it should be interpreted investigation.
with caution.
Dairy foods
Fruits and vegetables Studies on the effects of dairy food consumption on
In a 2018 meta-analysis of observational studies, increased cognitive function in individuals at a young age are
fruit and vegetable intake was associated with reduced scarce. One study reported an association between dairy
16
risk of cognitive impairment. However, evidence consumption at a young age and better cognitive
associating fruit and vegetable intake with cognitive outcomes at age 10 years.6 In addition, consumption of a
health across the life course has variable findings. In high dairy diet during a 12-week period improved scores
children and adolescents, a systematic review showed on spatial working memory compared with a low dairy
that consumption of healthy foods (including fruits and diet in adults who were overweight or obese (BMI ≥25).25
vegetables) was positively associated with executive Similarly, daily consumption of dairy products was
function, whereas consumption of unhealthy snack foods positively associated with various cognitive functions and
had a negative effect on executive function.17 positively associated with the outcomes of the MMSE
Fruits and
vegetables might not have the same effect on each compared with individuals who never or rarely consumed
cognitive domain. In a prospective cohort study of adults dairy foods.26 However, having more than one glass of
done over 13 years, intake of fruits and vegetables, fruits milk a day between the ages of 45 years and 64 years was
alone, and fruits with high vitamin C and vegetables were associated with a 10% decline in global cognitive
positively associated with verbal memory. However, 27
functioning and memory 20 years later. The type of
intake of fruit and vegetables, vegetables alone, and of dairy product or the fat content of the dairy product could
e750 www.thelancet.com/planetary-health Vol 6 September 2022
Review
affect this relationship, and sex differences might also be The evidence base in older adults is small. In a
present. For example, total dairy food consumption, 2020 study, exercise-induced improvements in age-
specifically cheese, was positively associated with associated cognitive function did not differ between
information processing speed and global cognitive exercise in combination with consumption of either 80 g
28 of cooked lean red meat or 80 g of carbohydrates. Both
perfor mance. Similarly, high intake of low-fat yogurt
was positively associated with memory recall in men, intervention groups showed improvements in global
35
whereas whole-fat dairy consumption (eg, ice cream and cognitive function and executive function. Meat
25
cream) was associated with cognitive deficits. consumption was not shown to have more of a detrimental
Regarding older adults, combined prospective analysis or beneficial effect than in the carbohydrate-consuming
of the Supplementation en Vitamines et Mineraux group. However, a 13-year follow-up of older adult women
Antioxydants (SU.VI.MAX)29 cohorts showed that total showed an increased likelihood of cognitive decline in
dairy product consumption was not associated with women who consumed low quantities of poultry and
cognitive function, but milk intake was negatively animal fats. These women also had an increased likeli-
associated with verbal memory performance. Moreover, hood of consuming high intakes of pastries and cakes,
36
women who consumed more than the daily recom- which could contribute to the observed cognitive decline.
mended amount of dairy showed worse working memory Compared with the lowest intake quartile, individuals in
30 the highest quartile of red meat intake at age 45–74 years
performance. By contrast, other studies indicate that
dairy consumption could be beneficial for older adults. had a higher risk of cognitive impairment at age
37
Increased frequency of cheese intake has been associated 61–96 years; this effect was weaker for poultry intake.
31
with decreased cognitive impairment. The Maine- Meat intake in childhood and early adulthood seems to
26 have little effect on cognition, with small amounts of
Syracuse Longitudinal Study revealed that the indivi-
duals who consumed the highest amounts of dairy evidence generally. However, the data indicate that red
products had the best cognitive performance on global meat intake in older adulthood can be associated with
cognition, visuospatial memory, and executive function cognitive deficits, but might have weak protective effects
compared with individuals who rarely consumed dairy in specific cognitive domains.
foods. From the scarce and inconclusive available
evidence, the effects of dairy consumption on cognitive Fish
performance could be dependent on dose, type, and fat The relationship between fish intake and cognitive
content. Further investigation of the effects of this food function is complex as fish contains beneficial nutrients,
group is required. such as long-chain n-3 polyunsaturated fatty acids
(PUFAs), but could also be a source of contaminants
Sources of protein (eg, mercury and dioxins). Children who consumed a
Meat spread made of fish flour for 6 months showed improved
Meat intake in the EAT–Lancet reference diet is divided verbal learning ability and memory compared with
into three categories: beef and lamb, pork, and chicken children who consumed a placebo spread made of
38
and other poultry. The reference diet advocates a reduced superfine rusk bread flour. When adjusting for dietary
meat intake, but specifies a recommended intake of three compliance, children who consumed an oily fish lunch
times as much chicken and other poultry than red meats. three times a week for 16 weeks showed improved
A systematic review of children and young adults intelligence scores compared with children who
showed sparse evidence for the effects of beef consumed a meat-based lunch.39 Cross-sectional evidence
consumption on cognitive function because of a small further indicates that consuming 8 g of fish per day in
number of studies, heterogeneous study designs, and childhood and adolescence increased the likelihood of
32
diverse study populations. Similarly, a systematic review high academic test scores by 1 point compared with
40
of adults published in 2020 found no association between individuals who consumed little or no fish. However, a
total meat intake and cognitive function or cognitive non-linear relationship is evident, in which academic
33
disorders. However, a sub-meta-analysis showed a achievement decreases with the highest amounts of fish
reduced likelihood of cognitive disorders in individuals consumption, potentially due to the presence of mercury
consuming meat once a week or more.33 Furthermore, a and other contaminants. High amounts of hair mercury,
large cohort study, comprising almost 500 000 participants, which were significantly associated with canned fish
showed that each additional portion per week of red meat intake but not total fish intake, were associated with
intake was associated with reduced cognitive function, deficits in general cognitive, memory, and verbal
41
such as reduced fluid intelligence and memory abilities. Similarly, high fish intake is associated with
34
performance. Some of these associations only occurred improved vocabulary and grades, but exceeding the
in men, such as those pertaining to reaction time, fluid recommended national guide lines for docosahexaenoic
intelligence, and prospective memory. There might be a 42
acid or eicosapentaenoic acid was not beneficial.
protective effect of increased red meat intake in both Studies of the effects of fish consumption on cognitive
men and women on visuospatial memory. function in adulthood are scarce. However, one
www.thelancet.com/planetary-health Vol 6 September 2022 e751
Review
cross-sectional study showed that although a high intake evidence coming from soy-based protein. Multiple
of seafood—particularly large-mouth fish, such as tuna— studies have investigated the effects of soy-based protein
increases amounts of mercury in the blood, it is also in postmenopausal women for durations between
associated with increased blood n-3 PUFAs. These 16 weeks and 2·5 years, but showed no effects on
increased n-3 PUFAs are associated with improved cognitive function.53–55
cognition (up to three servings of large-mouth fish per In older adults, high total bean and total soy-based
week). The positive effects of n-3 PUFAs can be product consumption showed favourable effects on
counteracted by high mercury intake, leading to worsened cognitive function in women.56 Moreover, a positive
cognitive function when plasma mercury concentrations association between high legume consumption and
43 57
are more than 15 μg/L. improvement in MMSE score after 1 year was shown. By
The long-term protective effects of fish against contrast, high tofu intake, a soy-based food, has been
cognitive decline in older adults have been shown consistently shown to impair memory and verbal learning
repeatedly. Consuming at least four servings of fish per in old age.58,59 In men, poor cognitive test performance
week leads to memory scores similar to individuals who and indications of increased brain atrophy were also
are 4 years younger.44 significantly associated with high tofu consumption in
Consuming one fish meal per week
60
is associated with a 10% reduction in the rate of cognitive adulthood.
decline and consuming two fish meals per week is
associated with a 13% reduction in the rate of cognitive Nuts
45
decline. In a Japanese cohort, there was an inverse A 2019 systematic review of nut consumption across the
association between fish consumption and the onset of life course revealed potential protective effects on some
61
dementia, with an odds ratio of 0·84. This inverse cognitive domains. However, cross-sectional and
association could lead to 5·6% fewer cases of dementia, 61
prospective cohort studies have unclear results. These
which equates to 2·6 million preventable cases worldwide protective effects also seem to be independent of the type
if fish intake is equivalent to the highest quintile of of nuts consumed, amount of nuts consumed, and
consumption (eg, >85·7 g/day).46 participant age. In a randomised controlled trial (RCT) of
Participants in the
Older People And n-3 Long-chain Polyunsaturated Fatty young adults aged between 18 years and 25 years,
47 inferential verbal reasoning was significantly improved
Acids cohort who reported regular consumption of oily
fish performed consistently better on cognitive tests. after 8 weeks of consuming walnut-containing banana
Furthermore, participants who reported eating the bread compared with placebo-containing banana bread,
largest amounts of oily fish, distinct from white fish, with no apparent effects on memory and non-verbal
48 reasoning.62
showed the highest rates of cognitive function. However, long-term almond con sumption
However, some studies have shown little to no did not improve cognitive function when consumed by
beneficial effect of fish consumption. An analysis of the adults who were overweight or obese (BMI 25–40) as part
63
SU.VI.MAX study found no association between fish of a weight loss intervention.
intake and MMSE performance, although a high self- Evidence indicates that nuts might positively affect
reported consumption of fish was associated with fewer cognitive function. A large sample of older adult women
49
cognitive complaints. Although cognitive complaints showed positive associations between high long-term
are self-reported and highly subjective, this outcome is nut intake and mean cognitive status for all cognitive
indicative of an improved quality of life. outcomes that were measured. Furthermore, women
consuming at least five servings of nuts per week had
Eggs better global cognition than women who did not
64
No studies have assessed the effects of egg consumption consume nuts. A cross-sectional analysis of the China
65
on cognitive function in young age. In older adults, a 4-year Health and Nutrition Survey cohort showed that
follow-up of men showed a positive association between individuals who consumed more than 10 g of nuts per
high egg intake and cognitive function. Specifically, each day had significantly higher global cognitive function
additional half egg per day was associated with improved scores than individuals who consumed less than 10 g of
performance on the trail-making test and verbal fluency nuts per day. Furthermore, only 8·4% of individuals who
test.50 consumed high amounts of nuts showed poor cognitive
However, these improvements were not replicated in
51 function compared with 17·8% of individuals who did
participants from the Health and Retirement Study.
Although moderate egg consumers (individuals who not consume nuts.66
ate two to six eggs per week) had the best cognitive However, an RCT published in 2020 contradicted these
performance at baseline, there was no association between 67
findings. A diet intervention with walnuts for a period of
egg consumption and cognitive change long term.52 2 years, accounting for 15% of the total daily energy
intake compared with a control group who did not have
Legumes walnuts, showed no delay in cognitive decline. However,
Research investigating the effect of chronic legume this RCT was conducted at two separate sites; a subset of
consumption on cognitive function is scarce, with most participants from one site who showed improved global
e752 www.thelancet.com/planetary-health Vol 6 September 2022
no reviews yet
Please Login to review.
