diet

Lipoprotein(a)

Author/s: 
Samia Mora, Florian Kronenberg

Lipoprotein(a) is a low-density lipoprotein-like particle that carries oxidized phospholipids and has proinflammatory and proatherogenic properties. In prospective studies, higher levels of lipoprotein(a) are associated with significantly higher risk of atherosclerotic cardiovascular disease (ASCVD) and all-cause mortality.1 In a meta-analysis of 29 069 patients, the incidence of ASCVD events per 1000 person-years was 80.0 (95% CI, 75.3-84.9) among people with lipoprotein(a) greater than or equal to 50 mg/dL and 55.3 (95% CI, 53.4-57.3) for people with lipoprotein(a) less than 15 mg/dL (adjusted hazard ratio, 1.35 [95% CI, 1.11-1.66]).2 A similar association of elevated lipoprotein(a) with ASCVD was observed among 460 506 participants from the UK Biobank study.3 Medications such as pelacarsen, olpasiran, and lepodisiran reduce lipoprotein(a) production in the liver and lower plasma lipoprotein(a) by up to 99%, and are currently undergoing testing in randomized clinical trials to determine whether they reduce rates of ASCVD in people with elevated lipoprotein(a).4

Diets

Author/s: 
Mary Yannakoulia, Nikolaos Scarmeas

Food consumption provides essential and nonessential nutrients in the human body and thereby promotes growth and health. Individual food choice and the potential modification of eating habits are complex issues, influenced by the availability and acceptability of foods.1 The availability of foods depends on physical, political, and economic factors. From the myriad foods that are available or potentially available for consumption, the selection is based on socioeconomic, cultural, and individual factors. Individual foods are parts of diets; diets are characterized by nutrient content, clustering of foods, and temporal consumption patterns. The plethora of diets continually expands, and some diets have been extensively investigated.
We review the underlying rationale for and constituents of the most widely recognized, scientifically explored, and broadly promoted diets (Figure 1). We do not review diets for specific nutritional or metabolic deficiencies or many of the constructed dietary indexes. This review is not intended to detail the clinical efficacy of each diet presented, although we briefly outline some of the well-known potential effects on health and the underlying mechanisms. Even though most (but not all) of the dietary modifications have been driven by the desire to control body weight, we consider important health effects independently of adiposity.

Keywords 

Approach to Obesity Treatment in Primary Care: A Review

Author/s: 
Susan Z Yanovski, Jack A Yanovski

Importance: More than 40% of US adults have obesity, which increases the risks for multiple chronic diseases and premature mortality. Historically, nonsurgical interventions often have not led to sufficient weight loss and maintenance to improve health, but highly effective antiobesity medications (AOMs) have recently become available, and additional effective therapeutics are under development. Given that most medical care for adults with obesity is delivered in primary care settings, guidance for integrating weight-management approaches is needed.

Observations: Lifestyle interventions can lead to a mean weight loss of 2% to 9% of initial weight at 1 year and increase the likelihood of weight loss of 5% or more, but weight regain over time is common even with continued treatment. Adjunctive treatments, including AOMs and surgical approaches, can lead to larger, more sustained weight loss and improvements in numerous obesity-associated medical conditions. Highly effective AOMs, including nutrient-stimulated hormone-based therapies, induce mean weight loss of 15% or more. Barriers to intervention, including access to care, have a disproportionate influence on populations most affected by obesity and its consequences.

Conclusions and relevance: Primary care clinicians play a vital role in the assessment, management, and support of patients with obesity. With careful clinical assessment and shared decision-making, a flexible treatment plan can be developed that reflects evidence of treatment efficacy, patient preference, and feasibility of implementation. Adjunctive therapies to lifestyle interventions, including more effective pharmacotherapeutics for obesity, offer hope to patients and the potential for considerable improvements in health and quality of life.

What Is Alpha-Gal Syndrome?

Author/s: 
Fatema Mollah, Mark A Zacharek, Mariel R Benjamin

Alpha-gal syndrome is a type of food allergy to mammalian (red) meat products.

Alpha-gal syndrome is associated with tick bites, most commonly from the Lone Star tick in the US, but also from different types of ticks in other areas of the world. During a bite, a tick injects a type of sugar molecule (galactose-alpha-1,3-galactose), also called alpha-gal, which leads to formation of an antibody. Because alpha-gal is present on cells of most mammals, including cows, pigs, lambs, and goats, when affected individuals eat these animal products, an allergic reaction may occur.

Dietary recommendations for prevention of atherosclerosis

This review aims at summarizing updated evidence on cardiovascular disease (CVD) risk associated with consumption of specific food items to substantiate dietary strategies for atherosclerosis prevention. A systematic search on PubMed was performed to identify meta-analyses of cohort studies and RCTs with CVD outcomes. The evidence is highly concordant in showing that, for the healthy adult population, low consumption of salt and foods of animal origin, and increased intake of plant-based foods—whole grains, fruits, vegetables, legumes, and nuts—are linked with reduced atherosclerosis risk. The same applies for the replacement of butter and other animal/tropical fats with olive oil and other unsaturated-fat-rich oil. Although the literature reviewed overall endorses scientific society dietary recommendations, some relevant novelties emerge. With regard to meat, new evidence differentiates processed and red meat—both associated with increased CVD risk—from poultry, showing a neutral relationship with CVD for moderate intakes. Moreover, the preferential use of low-fat dairies in the healthy population is not supported by recent data, since both full-fat and low-fat dairies, in moderate amounts and in the context of a balanced diet, are not associated with increased CVD risk; furthermore, small quantities of cheese and regular yogurt consumption are even linked with a protective effect. Among other animal protein sources, moderate fish consumption is also supported by the latest evidence, although there might be sustainability concerns. New data endorse the replacement of most high glycemic index (GI) foods with both whole grain and low GI cereal foods. As for beverages, low consumption not only of alcohol, but also of coffee and tea is associated with a reduced atherosclerosis risk while soft drinks show a direct relationship with CVD risk. This review provides evidence-based support for promoting appropriate food choices for atherosclerosis prevention in the general population.

Dietary Approaches to Improve Efficacy and Control Side Effects of Levodopa Therapy in Parkinson's Disease: A Systematic Review

Author/s: 
Boelens Keun, J., Arnoldussen, I., Vriend, C., Van de Rest, O.

Although levodopa remains the most effective drug for symptomatic management of Parkinson's Disease (PD), treatment during advanced disease stages may raise unpredictable motor fluctuations and other complications. Counteracting these complications with other pharmacological therapies may prompt a vicious circle of side effects, and here, nutritional therapy may have great potential. Knowledge about the role of diet in PD is emerging and multiple studies have investigated nutritional support specifically with respect to levodopa therapy. With this systematic review, we aim to give a comprehensive overview of dietary approaches to optimize levodopa treatment in PD. A systematic search was performed using the databases of PubMed and Scopus between January 1985 and September 2020. Nutritional interventions with the rationale to optimize levodopa therapy in human PD patients were eligible for this study and their quality was assessed with the Cochrane risk-of-bias tool. In total, we included 22 papers that addressed the effects of dietary proteins (n = 10), vitamins (n = 7), fiber (n = 2), soybeans (n = 1), caffeine (n = 1), and ketogenic diets (n = 1) on levodopa therapy. Interventions with protein redistribution diets (PRDs), dietary fiber, vitamin C, and caffeine improved levodopa absorption, thereby enhancing clinical response and reducing motor fluctuations. Furthermore, supplementation of vitamin B-12, vitamin B-6, and folic acid successfully reduced high homocysteine concentrations that emerged from levodopa metabolism and promoted many metabolic and clinical complications, such as neuropathology and osteoporosis. In conclusion, dietary interventions have the potential to optimize levodopa efficacy and control side effects. Nutrition that improves levodopa absorption, including PRDs, fiber, vitamin C, and caffeine, is specifically recommended when fluctuating clinical responses appear. Supplements of vitamin B-12, vitamin B-6, and folic acid are advised along with levodopa initiation to attenuate hyperhomocysteinemia, and importantly, their potential to treat consequent metabolic and clinical complications warrants future research.

Can We Say What Diet Is Best for Health?

Author/s: 
Katz, DL, Meller, S

Diet is established among the most important influences on health in modern societies. Injudicious diet figures among the leading causes of premature death and chronic disease. Optimal eating is associated with increased life expectancy, dramatic reduction in lifetime risk of all chronic disease, and amelioration of gene expression. In this context, claims abound for the competitive merits of various diets relative to one another. Whereas such claims, particularly when attached to commercial interests, emphasize distinctions, the fundamentals of virtually all eating patterns associated with meaningful evidence of health benefit overlap substantially. There have been no rigorous, long-term studies comparing contenders for best diet laurels using methodology that precludes bias and confounding, and for many reasons such studies are unlikely. In the absence of such direct comparisons, claims for the established superiority of any one specific diet over others are exaggerated. The weight of evidence strongly supports a theme of healthful eating while allowing for variations on that theme. A diet of minimally processed foods close to nature, predominantly plants, is decisively associated with health promotion and disease prevention and is consistent with the salient components of seemingly distinct dietary approaches. Efforts to improve public health through diet are forestalled not for want of knowledge about the optimal feeding of Homo sapiens but for distractions associated with exaggerated claims, and our failure to convert what we reliably know into what we routinely do. Knowledge in this case is not, as of yet, power; would that it were so.

Unprocessed Red Meat and Processed Meat Consumption: Dietary Guideline Recommendations From the Nutritional Recommendations (NutriRECS) Consortium

Author/s: 
Johnston, BC, Zeraatkar, D, Han, MA, Vernooij RWM, Valli, C, El Dib, R, Marshall, C, Stover, PJ, Fairweather-Taitt, S, Wojcik, G, Bhatia, F, de Souza, R, Brotons, C, Meerpohl, JJ, Patel, CJ, Djulbegovic, B, Alonso-Coello, P, Bala, MM, Guyatt, GH

DESCRIPTION:

Dietary guideline recommendations require consideration of the certainty in the evidence, the magnitude of potential benefits and harms, and explicit consideration of people's values and preferences. A set of recommendations on red meat and processed meat consumption was developed on the basis of 5 de novo systematic reviews that considered all of these issues.

METHODS:

The recommendations were developed by using the Nutritional Recommendations (NutriRECS) guideline development process, which includes rigorous systematic review methodology, and GRADE methods to rate the certainty of evidence for each outcome and to move from evidence to recommendations. A panel of 14 members, including 3 community members, from 7 countries voted on the final recommendations. Strict criteria limited the conflicts of interest among panel members. Considerations of environmental impact or animal welfare did not bear on the recommendations. Four systematic reviews addressed the health effects associated with red meat and processed meat consumption, and 1 systematic review addressed people's health-related values and preferences regarding meat consumption.

RECOMMENDATIONS:

The panel suggests that adults continue current unprocessed red meat consumption (weak recommendation, low-certainty evidence). Similarly, the panel suggests adults continue current processed meat consumption (weak recommendation, low-certainty evidence).

PRIMARY FUNDING SOURCE:

None. (PROSPERO 2017: CRD42017074074; PROSPERO 2018: CRD42018088854)

Changes in nut consumption influence long-term weight change in US men and women

Author/s: 
X, Li, Y, Guasch-Ferre, M, Willett, WC, Drouin-Chartier, JP, Bhupathiraju, SN, Tobias, DK

Background Nut consumption has increased in the US but little evidence exists on the association between changes in nut consumption and weight change. We aimed to evaluate the association between changes in total consumption of nuts and intakes of different nuts (including peanuts) and long-term weight change, in three independent cohort studies.

Methods and findings Data collected in three prospective, longitudinal cohorts among health professionals in the US were analysed. We included 27 521 men (Health Professionals Follow-up Study, 1986 to 2010), 61 680 women (Nurses’ Health Study, 1986 to 2010), and 55 684 younger women (Nurses’ Health Study II, 1991 to 2011) who were free of chronic disease at baseline in the analyses. We investigated the association between changes in nut consumption over 4-year intervals and concurrent weight change over 20–24 years of follow-up using multivariate linear models with an unstructured correlation matrix to account for within-individual repeated measures. 21 322 individuals attained a body mass index classification of obesity (BMI ≥30 kg/m2) at the end of follow-up.

Average weight gain across the three cohorts was 0.32 kg each year. Increases in nut consumption, per 0.5 servings/day (14 g), was significantly associated with less weight gain per 4-year interval (p<0.01 for all): −0.19 kg (95% CI -0.21 to -0.17) for total consumption of nuts, -0.37 kg (95% CI -0.45 to -0.30) for walnuts, -0.36 kg (95% CI -0.40 to -0.31) for other tree nuts, and -0.15 kg (95% CI -0.19 to -0.11) for peanuts.

Increasing intakes of nuts, walnuts, and other tree nuts by 0.5 servings/day was associated with a lower risk of obesity. The multivariable adjusted RR for total nuts, walnuts, and other tree nuts was 0.97 (95% CI 0.96 to 0.99, p=0.0036), 0.85 (95% CI 0.81 to 0.89, p=0.0002), and 0.89 (95% CI 0.87 to 0.91, p<0.0001), respectively. Increasing nut consumption was also associated with a lower risk of gaining ≥2 kg or ≥5 kg (RR 0.89–0.98, p<0.01 for all).

In substitution analyses, substituting 0.5 servings/day of nuts for red meat, processed meat, French fries, desserts, or potato, chips (crisps) was associated with less weight gain (p<0.05 for all).

Our cohorts were largely composed of Caucasian health professionals with relatively higher socioeconomic status; thus the results may not be generalisable to other populations.

Conclusion Increasing daily consumption of nuts is associated with less long-term weight gain and a lower risk of obesity in adults. Replacing 0.5 servings/day of less healthful foods with nuts may be a simple strategy to help prevent gradual long-term weight gain and obesity.

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