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Mediterranean and Western diet effects on Alzheimer's disease biomarkers, cerebral perfusion, and cognition in mid-life: A randomized trial.
Hoscheidt, S, Sanderlin, AH, Baker, LD, Jung, Y, Lockhart, S, Kellar, D, Whitlow, CT, Hanson, AJ, Friedman, S, Register, T, et al
Alzheimer's & dementia : the journal of the Alzheimer's Association. 2022;18(3):457-468
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There is a current understanding that Alzheimer’s disease (AD) development is related to a high intake of saturated fat and simple carbohydrates, which are found in abundance in the so-called Western Diet (WD). In contrast the consumption of low saturated fat and simple carbohydrates characteristic of the Mediterranean Diet (MD), has been associated with a reduced risk for the development of AD. This study aimed to look at the association of the MD and WD with AD in a more robust way using the randomised control method in 84 individuals both with and without mild memory impairment. The results showed that depending on whether an individual has mild brain impairment determines their response to the MD or WD after 4 weeks. In those without brain impairment the adoption of the WD resulted in a shift towards increasing the risk for AD development and the reverse following the MD. Whereas in those with brain impairment, the adoption of the WD was protective against the development of AD and the MD moved individuals towards worse disease outcomes. It was concluded that diet can be of importance in the prevention or progression of AD and that further studies are required to determine the possible mechanisms through which these two diets can act differentially. This study could be used by health care professionals to understand that diet can have a large impact on AD.
Expert Review
Conflicts of interest:
None
Take Home Message:
- A Med-diet may be beneficial for supporting brain health, cognitive function. metabolic health and reduce the risk of an AD pathology in middle-aged adults with normal cognitive function
Evidence Category:
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X
A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)
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B: Systematic reviews including RCTs of limited number
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C: Non-randomized trials, observational studies, narrative reviews
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D: Case-reports, evidence-based clinical findings
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E: Opinion piece, other
Summary Review:
Introduction
Epidemiological studies have associated a Western diet (West-diet) with an increased risk of Alzheimer’s disease (AD) and other dementias. This study aimed to examine the impact of a Mediterranean-diet (Med-diet) versus a West-diet on AD pathology, cognition, vascular function and metabolic markers in middle aged adults with normal cognitive (NC) function compared to adults with mild cognitive impairment (MCI).
Methods
N=41 NC adult females completed the Med-diet and N=43 adult females with MCI completed the West-diet arm of this study. The average age of the participants was 56y. All participants received isocaloric diets which were either high or low in saturated fat, sodium and glycaemic index (GI) for 4 weeks. Statistical analyses were conducted per dietary arm as well as per cognitive function (NC vs MCI).
Results
- NC Participants were found to have decreased cerebro-spinal fluid (CSF) biomarkers (p=.026) following the Med-diet and increased levels following the West-diet. Whereas, cerebral perfusion increased following the med-diet and decreased after the West-diet (p=.003). These results indicate a reduced AD risk. The MCI group showed no changes to CSF or cerebral perfusion for either dietary group.
- Cognition tended to improve for the NC Med-diet and remain the same for the NC West-diet group. No changes were found for the MCI groups.
- Total cholesterol levels were increased following the West-diet and decreased following the Med-diet for both groups (p=0.0001).
- Glucose and HbA1C were unchanged in the NC group following the Med-diet, increased for the West-diet (p=.049) and decreased for the MCI group (p=<.001). whereas fasting insulin was increased in the NC Med-diet group and decreased in the MCI Med-diet (p=.0.12) and West diet groups.
Conclusion
The results of this study found that diet may modulate AD pathology, cognitive and metabolic function in middle-aged adults. A West-like diet may increase risk of AD through its effects on impairing cognitive function, reducing cerebral infusion and negatively influencing metabolic health in NC adults. Conversely, A Med-diet may promote brain function and metabolic health. However, surprisingly, in this study the results were reversed for MCI middle aged adults, the results showed improvement in metabolic and cerebrospinal fluid biomarkers for the West-diet. These results require further confirmation.
No conflicts of interest were declared.
Clinical practice applications:
- A Med-diet may be beneficial for supporting brain health, cognitive function, metabolic health and reducing the risk of an AD pathology in middle-aged adults with normal cognitive function but not for those with MCI.
Considerations for future research:
The authors acknowledged several limitations to this study.
- These results require further confirmation through longer and larger studies, particularly the surprising finding that a West-diet may confer beneficial effects on metabolic and brain health for middle-aged adults with MCI.
Abstract
INTRODUCTION Mid-life dietary patterns are associated with Alzheimer's disease (AD) risk, although few controlled trials have been conducted. METHODS Eighty-seven participants (age range: 45 to 65) with normal cognition (NC, n = 56) or mild cognitive impairment (MCI, n = 31) received isocaloric diets high or low in saturated fat, glycemic index, and sodium (Western-like/West-diet vs. Mediterranean-like/Med-diet) for 4 weeks. Diet effects on cerebrospinal fluid (CSF) biomarkers, cognition, and cerebral perfusion were assessed to determine whether responses differed by cognitive status. RESULTS CSF amyloid beta (Aβ)42/40 ratios increased following the Med-diet, and decreased after West-diet for NC adults, whereas the MCI group showed the reverse pattern. For the MCI group, the West-diet reduced and the Med-diet increased total tau (t-tau), whereas CSF Aβ42 /t-tau ratios increased following the West-diet and decreased following the Med-diet. For NC participants, the Med-diet increased and the West-diet decreased cerebral perfusion. DISCUSSION Diet response during middle age may highlight early pathophysiological processes that increase AD risk.
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The Weight Optimization Revamping Lifestyle using the Dietary Guidelines (WORLD) Study: Sustained Weight Loss Over 12 Months.
Psota, TL, Tindall, AM, Lohse, B, Miller, PE, Petersen, KS, Kris-Etherton, PM
Obesity (Silver Spring, Md.). 2020;28(7):1235-1244
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Effective long-term weight loss strategies to reduce the risk of death and diseases associated with being obese or overweight are required, as restrictive programmes are difficult to sustain, and weight loss may be heavily influenced by behavioural factors. This randomised control trial of 101 premenopausal women with obesity or overweight aimed to compare a lower-fat and moderate-fat diets, both with nutrition education for 12 months. The results showed that both treatment groups lost weight. Both groups consumed the same amount of fat but increased their diet quality. Diet quality and greater attendance at nutritional education sessions were associated with greater weight loss. Cholesterol was significantly lower in both groups, but blood pressure remained unchanged. Interestingly there were a large number of women who did not complete the trial. It was concluded that irrespective of the amount of fat consumed, nutrition education can help to achieve sustained weight loss, improve diet quality and decrease heart disease risk for at least 12 months. This study could be used by healthcare professionals to understand that recommending fat-based targets for weight loss may be ineffective and the importance of emotional and behavioural support for individuals on a weight loss regime to improve their risk for heart disease.
Abstract
OBJECTIVE This study aimed to compare two energy-restricted, nutrient-dense diets at the upper or lower ends of the dietary fat recommendation range (lower fat [20% energy from fat] versus moderate fat [35%]) on weight loss using behavioral theory-based nutrition education. METHODS A total of 101 premenopausal women with overweight or obesity were randomized to an energy-restricted lower-fat or moderate-fat diet for 1 year. Interventions included 28 behavioral theory-based nutrition education sessions plus weekly exercise sessions. RESULTS Both treatment groups experienced weight loss (-5.0 kg for lower fat and -4.3 kg for moderate fat; P < 0.0001), but there was no difference in weight loss or fat intake between groups. Total and low-density lipoprotein cholesterol decreased (-3. 4 mg/dL and -3.8 mg/dL; P < 0.05), and high-density lipoprotein cholesterol increased (1.9 mg/dL; P < 0.05) in both groups at 12 months. Diet quality, assessed by the Healthy Eating Index, increased significantly at 4 months versus baseline (70.8 [0.9] vs. 77.8 [1.0]) and was maintained through 12 months. Higher Healthy Eating Index scores were associated with greater weight loss at 4 months (r = -0.2; P < 0.05). CONCLUSIONS In the context of a well-resourced, free-living weight-loss intervention, total fat intake did not change; however, theory-based nutrition education underpinned by food-based recommendations resulted in caloric deficits, improvements in diet quality, and weight loss that was sustained for 1 year.
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Lipid profile is associated with decreased fatigue in individuals with progressive multiple sclerosis following a diet-based intervention: Results from a pilot study.
Fellows Maxwell, K, Wahls, T, Browne, RW, Rubenstein, L, Bisht, B, Chenard, CA, Snetselaar, L, Weinstock-Guttman, B, Ramanathan, M
PloS one. 2019;14(6):e0218075
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Fatigue is a frequent and debilitating symptom of multiple sclerosis (MS) and is independent of level of disability. The authors previously reported that a 12 months diet and lifestyle intervention was effective at reducing fatigue in patients with progressive MS. The aims of this study were to characterise the changes in lipid and cholesterol biomarkers during the intervention, and to investigate whether these biomarkers were associated with fatigue outcomes. Data of 18 MS patients were analysed. The intervention consisted of a modified Paleolithic diet, supplemented with exercise, neuromuscular electrical stimulation (NMES) and stress reduction techniques (Wahl’s protocol). Fatigue was significantly decreased at 3, 6, 9 and 12 months compared to baseline, and more so in those having more of the recommended foods and less of the excluded foods. The exercise, NMES, and stress reduction components of the intervention were not associated with changes in fatigue. All variables of the lipid profiles improved during the 12 months intervention. These improvements were associated with the changes in nutrient intakes, in particular, with amounts and types of fat, carbohydrates and fibre. Changes in total and HDL cholesterol, but not LDL cholesterol or triglycerides were associated with a decrease in fatigue. The authors hypothesise that the benefits of the changes in lipid profile on fatigue may be mediated by the positive effects of HDL-cholesterol on mitochondrial function (mitochondria are the “power houses” of every cell, i.e. produce energy on the cellular level), in particular those in the muscles. Limitations of the study include the small sample size, lack of control group and randomisation. The authors conclude that diet-induced changes in HDL and total cholesterol may mediate the positive effects of a dietary and lifestyle intervention on fatigue in MS patients.
Abstract
PURPOSE To investigate associations between lipid profiles and fatigue in a cohort of progressive multiple sclerosis (MS) patients on a diet-based multimodal intervention. METHODS This pilot study included 18 progressive MS patients who participated in a prospective longitudinal study of fatigue following a diet-based multimodal intervention that included exercise, neuromuscular electrical stimulation and stress reduction. The diet recommended high intake of vegetables and fruits, encouraged consumption of animal and plant protein and excluded foods with gluten-containing grains, dairy and eggs. Fatigue was measured on the Fatigue Severity Scale (FSS) at baseline and every 3 months for 12 months. A lipid profile consisting of high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), total cholesterol (TC) and triglycerides (TG) was obtained on fasting blood samples at baseline and 12 months. RESULTS FSS scores decreased from a baseline of 5.51 (95% CI: 4.86, 6.16) to a mean of 3.03 (95% CI: 2.23, 3.82) at 12 months (p < 0.001). At 12 months, increases in HDL-C (mean change: +6.0 mg/dl; 95% CI: 0.3, 12.0; p = 0.049) and decreases in BMI (mean change: -2.6 kg/m2; 95% CI: -3.6, -2.5; p < 0.001), LDL-C (mean change: -10.4 mg/dl; 95% CI:-19.7, -1.2; p = 0.029), TG (mean change: -29.2 mg/dl; 95% CI: -44.3, -14.2; p = 0.001), TG to HDL-C ratio (mean change: -0.6; 95% CI: -1.0, -0.3; p = 0.002) and TC to HDL-C ratio (mean change:-0.6; 95% CI: -1.0, -0.3; p = 0.003) were observed compared to baseline. Improvements in FSS were associated with increases in HDL-C (β = -0.05; 95% CI: -0.1, -0.0004; p = 0.048) and changes in TC (p = 0.005) from baseline to 12 months. CONCLUSIONS Lipid profile variables are associated with improvements in fatigue in progressive MS patients on a diet-based multimodal intervention.
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Estrogen and progesterone exposure is reduced in response to energy deficiency in women aged 25-40 years.
Williams, NI, Reed, JL, Leidy, HJ, Legro, RS, De Souza, MJ
Human reproduction (Oxford, England). 2010;25(9):2328-39
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Diet and exercise are related to a reduction in breast cancer risk, and it is thought that this is at least partly due to their impact on levels of female sex hormones. This study aimed to test the effect that exercise and calorie restriction have on menstruation and sex hormones in premenopausal women. Inactive women aged 25-40 years were recruited for the study, and allocated to two groups. One group was assigned a low-calorie diet that provided 20-35% lower calories than baseline energy needs, plus 4 sessions of moderate-intensity exercise per week. The control group followed a diet designed to ensure weight maintenance, and took part in shorter exercise sessions twice a week. Women in the low-calorie group experienced a 15% reduction in levels of oestradiol and a 20% reduction in the levels of oestrogen metabolite oestrone glucuronide. Larger reductions in oestrone glucuronide were related to higher energy deficits, suggesting that hormone production is sensitive to day-to-day fluctuations in energy balance. There was no change in the menstrual cycles of the participants. The researchers concluded that an energy deficit is a more important factor in reducing oestrogen exposure than losing weight.
Abstract
BACKGROUND Alterations in circulating steroids are believed to be important mediators of the impact that diet and exercise have on breast cancer risk and changes in bone density. This study aimed to test the hypothesis that moderate exercise training combined with caloric restriction would produce significant menstrual disturbances and alterations in ovarian steroids in premenopausal women. METHODS Sedentary premenopausal women (25-40 years; body mass index: 23.6 +/- 0.6 kg/m(2)) assigned to either a light conditioning (LC, n = 9) or an exercise combined with caloric restriction group (EX + CR, n = 24) were studied for one screening, one baseline and four intervention periods equivalent to the length of subjects' menstrual cycles. Exercise consisted of supervised training sessions, i.e. two LC or four EX + CR times per week, 30-60 min at a moderate intensity. The EX + CR group was prescribed a diet representing a caloric restriction of 20-35% below baseline energy requirements, whereas the LC group remained eucaloric. Ovarian steroid exposure was determined with daily urinary estrone-1- and pregnanediol glucuronides (E1G and PdG, respectively) and mid-cycle urinary LH measures. Fitness, body composition, and serum sex hormone binding globulin (SHBG) and serum estradiol (E2) were assessed repeatedly. RESULTS The intervention produced significant increases in VO(2) max and decreases in both body weight (-3.7 +/- 0.5 kg; ranged from -8.8 to +1.8 kg) and percent body fat (-4.5 +/- 0.7%; ranged from -12 to +0.3%), which were attributable primarily to changes in the EX + CR subjects (time x group; P < 0.05). Serum E2 and urinary E1G and PdG concentrations declined significantly across the intervention period (time; P < 0.05), whereas SHBG increased transiently (time; P < 0.05) in the EX + CR subjects, with no significant changes observed in the LC group. The decrease in E1G area under the curve was significantly related to the daily energy deficit (R =0.61; P = 0.003), not the amount of weight lost. There was no significant impact of the intervention on menstrual cyclicity or the incidence of menstrual disturbances in either group. CONCLUSIONS A moderate aerobic exercise training program combined with modest weight loss in accordance with recommended guidelines produces significant reductions in ovarian steroid exposure without disrupting menstrual cyclicity in premenopausal women aged 25-40 years. Exposure to a daily energy deficit is a stronger predictor of the decline in estrogen exposure than decreases in body weight.