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Journal of the International Society of... Dec 2024The International Society of Sports Nutrition (ISSN) provides an objective and critical review of the use of a ketogenic diet in healthy exercising adults, with a focus... (Review)
Review
POSITION STATEMENT
The International Society of Sports Nutrition (ISSN) provides an objective and critical review of the use of a ketogenic diet in healthy exercising adults, with a focus on exercise performance and body composition. However, this review does not address the use of exogenous ketone supplements. The following points summarize the position of the ISSN.
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1. A ketogenic diet induces a state of nutritional ketosis, which is generally defined as serum ketone levels above 0.5 mM. While many factors can impact what amount of daily carbohydrate intake will result in these levels, a broad guideline is a daily dietary carbohydrate intake of less than 50 grams per day.
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2. Nutritional ketosis achieved through carbohydrate restriction and a high dietary fat intake is not intrinsically harmful and should not be confused with ketoacidosis, a life-threatening condition most commonly seen in clinical populations and metabolic dysregulation.
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3. A ketogenic diet has largely neutral or detrimental effects on athletic performance compared to a diet higher in carbohydrates and lower in fat, despite achieving significantly elevated levels of fat oxidation during exercise (~1.5 g/min).
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4. The endurance effects of a ketogenic diet may be influenced by both training status and duration of the dietary intervention, but further research is necessary to elucidate these possibilities. All studies involving elite athletes showed a performance decrement from a ketogenic diet, all lasting six weeks or less. Of the two studies lasting more than six weeks, only one reported a statistically significant benefit of a ketogenic diet.
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5. A ketogenic diet tends to have similar effects on maximal strength or strength gains from a resistance training program compared to a diet higher in carbohydrates. However, a minority of studies show superior effects of non-ketogenic comparators.
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6. When compared to a diet higher in carbohydrates and lower in fat, a ketogenic diet may cause greater losses in body weight, fat mass, and fat-free mass, but may also heighten losses of lean tissue. However, this is likely due to differences in calorie and protein intake, as well as shifts in fluid balance.
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7. There is insufficient evidence to determine if a ketogenic diet affects males and females differently. However, there is a strong mechanistic basis for sex differences to exist in response to a ketogenic diet.
Topics: Diet, Ketogenic; Humans; Athletic Performance; Sports Nutritional Physiological Phenomena; Body Composition; Ketosis; Sports Nutritional Sciences; Dietary Carbohydrates; Exercise; Physical Endurance
PubMed: 38934469
DOI: 10.1080/15502783.2024.2368167 -
Obesity Facts Jun 2024Primary prevention is a public health strategy that hitherto has not been widely applied in obesity prevention research. The objectives were to examine the long-term...
INTRODUCTION
Primary prevention is a public health strategy that hitherto has not been widely applied in obesity prevention research. The objectives were to examine the long-term effects of the Healthy Start primary obesity prevention study, an intervention conducted among healthy weight children susceptible to develop obesity.
METHODS
At baseline, children (2-6 years) were randomized allocated to the intervention group (n=271), the control group (n=272), or the shadow control group (n=383). Children in the shadow control group had no contact with project staff during the intervention period (1.3 years on average). The intervention was designed to deliver individually tailored improvements in diet and physical activity habits, optimization of sleep quantity and quality and reduce family stress. After the intervention was completed, height and weight at school entry was obtained from the Danish National Child Health Register when children were around 7 years. The average follow-up time was 2.7 years after baseline. Linear regression analyses on annual changes in BMI (ΔBMI) and BMI z-scores (ΔBMIz) were conducted.
RESULTS
At mean 2.7 years after the baseline examination, no differences were observed between the intervention and control group in ΔBMI (β=0.07 (-0.02;0.15), p=0.14) or ΔBMIz (β=0.03 (-0.05;0,11), p=0.45). Likewise, no differences were observed between the intervention and shadow control group in ΔBMI (β=-0.03 (-0.12;0.06), p=0.50) or in ΔBMIz (β=-0.02 (-0.08;0.05), p=0.62).
CONCLUSION
We are still in urgent need of more primary overweight prevention interventions to begin to understand how to prevent that healthy weight children develop overweight.
PubMed: 38934182
DOI: 10.1159/000540005 -
Frontiers in Nutrition 2024Our core premise is that personalized variations of a ketogenic diet are likely to benefit pediatric patients with neuropsychiatric symptoms across multiple domains....
Our core premise is that personalized variations of a ketogenic diet are likely to benefit pediatric patients with neuropsychiatric symptoms across multiple domains. Although pediatric epilepsy is currently a well-accepted indication for a strict ketogenic diet, there is a dearth of knowledge and therefore clinical guidelines upon which to recommend nutritional ketosis for pervasive pediatric conditions such as autism spectrum disorder and ADHD, even when comorbid epilepsy is present. However, there are published cohort studies and current clinical trials implementing medical ketogenic therapies for cognitive impairment, psychiatric comorbidities, motor disability, and even neuroinflammation. As holistic practitioners, it is imperative that we consider the health of a child in its entirety - and additionally offer the ketogenic diet as a therapeutic option when it may be synergistic in treating extra-neurologic diseases such as obesity. While there are uniquely pediatric potential adverse side effects such as linear growth deceleration and micronutrient deficiencies, previous trials in epilepsy and our center's experience have already proven the ketogenic diet to be a low-risk intervention when optimized with appropriate patient monitoring and support.
PubMed: 38933892
DOI: 10.3389/fnut.2024.1408327 -
Frontiers in Nutrition 2024
PubMed: 38933887
DOI: 10.3389/fnut.2024.1436894 -
Frontiers in Nutrition 2024Epidemiological studies show dietary habits can have an impact on the risk of cholelithiasis, but the relationship is still unclear. We used a comprehensive Mendelian...
BACKGROUND
Epidemiological studies show dietary habits can have an impact on the risk of cholelithiasis, but the relationship is still unclear. We used a comprehensive Mendelian randomization (MR) study to explore the relationship between dietary habits and cholelithiasis.
METHODS
The 18 dietary habits were divided into six categories: meat foods, cereals, vegetables, fruits, dairy products, beverages, and condiments. Cholelithiasis data came from a GWAS meta-analysis and the FinnGen consortium. The inverse variance weighted (IVW), the weighted median (WM), and MR-Egger approaches were used as the main MR analysis methods. In addition, multiple sensitivity analysis and meta-analysis were performed to verify the robustness of the results.
RESULTS
Dried fruit intake [odds ratio (OR) = 0.568; 95% confidence interval (CI), 0.405-0.797; = 0.001] was discovered to reduce the risk of cholelithiasis. The sensitivity analysis and meta-analysis showed reliable results for the relationship between dried fruit intake and cholelithiasis.
CONCLUSION
Our study found that dried fruit intake is a protective factor in the development of cholelithiasis. However, the mechanisms of action need to be further explored.
PubMed: 38933877
DOI: 10.3389/fnut.2024.1377631 -
Frontiers in Endocrinology 2024Tryptophan's (Trp) metabolites are undervalued markers of human health. Their serum concentrations are modified by physical exercise and other factors, among which...
INTRODUCTION
Tryptophan's (Trp) metabolites are undervalued markers of human health. Their serum concentrations are modified by physical exercise and other factors, among which fasting has a well-documented role. Although this mechanism is hardly explored, thus, the study aimed to determine the effect of the 8-day fasting period and the impact of such a procedure on a single bout of an endurance exercise on the concentration of kynurenine pathway (KP) metabolites.
METHODS
10 participants fasted for 8 days, and 10 as a control group participated in the study. The exercise was performed at baseline after an overnight fast and repeated post 8 days.
RESULTS
The 8 days of fasting increased the resting 3-hydroxy-L-kynurenine (3HK), picolinic acid (PA), kynurenic acid (KYNA), and xanthurenic acid (XA) serum concentration. Also elevated phenylalanine (Phe) and tyrosine (Tyr) levels were recorded, suggesting expanded proteolysis of muscle proteins. In turn, physical activity caused a decrease in the concentration of 3-hydroxyanthranilic acid (3HAA) and PA after fasting. The obtained results were not recorded in controls.
CONCLUSION
The results of this study show that the health-promoting effects of fasting are associated with changes in the KYN pathway. The increase in the concentration of PA and XA metabolites following fasting is capable of penetrating the blood-brain barrier, and KYNA, which initiates several beneficial changes, supports this assumption.
Topics: Humans; Male; Fasting; Kynurenine; Exercise; Adult; Young Adult; Rest; Healthy Volunteers; Kynurenic Acid; Tryptophan; Biomarkers; Picolinic Acids
PubMed: 38933822
DOI: 10.3389/fendo.2024.1403491 -
Frontiers in Endocrinology 2024Despite the fact that China amounts to one-fifth of the world's population, has a higher proportion of the elderly, and has a higher prevalence of osteoporosis and...
OBJECTIVE
Despite the fact that China amounts to one-fifth of the world's population, has a higher proportion of the elderly, and has a higher prevalence of osteoporosis and fracture, limited studies have investigated the association between dietary patterns and bone mineral density (BMD) as well as fracture risk among the elderly Chinese population. We aimed to investigate the association between different dietary patterns and BMD as well as the risk of fractures, and this association may vary between elderly women and men.
METHODS
Building upon the China Osteoporosis Prevalence Study, we included 17,489 subjects aged ≥40 years old randomly sampled across 44 counties/districts of 11 provinces or municipalities in China who completed a food frequency questionnaire. BMD was measured by dual x-ray absorptiometry. Vertebral fracture was defined based on lateral spine radiographs using the semi-quantitative technique of Genant.
RESULTS
A diet rich in "carnivorous", "vegetarian", "dairy, fruit, and egg" was significantly associated with higher BMD at total hip (TH), femoral neck (FN), and lumbar spine 1-4 (L1-4). Yet, a diet rich in "beverage and fried food" was associated with a lower BMD at the FN and L1-4. High quartiles of the carnivorous diet were associated with 34%-39% reduced risk of clinical fracture in the past 5 years and vertebral fracture. Stronger associations were observed among women. Sensitivity analysis among postmenopausal women presented even stronger positive associations between carnivorous and vegetarian diets and high BMD, as well as between carnivorous diet and reduced risk of fractures.
CONCLUSIONS
Our study suggested that a diet rich in meat, vegetables, and dairy, fruit, and eggs might be associated with greater BMD and a lower fracture risk, while beverage and fried foods may be associated with a lower BMD at L1-4, especially among elderly women. These findings are relevant to provide recommendations on dietary nutrition regarding the elderly population at high risk of osteoporosis and fractures, especially postmenopausal women.
Topics: Humans; Bone Density; Female; China; Aged; Middle Aged; Prevalence; Osteoporosis; Diet; Male; Risk Factors; Osteoporotic Fractures; Absorptiometry, Photon; Fractures, Bone; Feeding Behavior; Cross-Sectional Studies; Dietary Patterns
PubMed: 38933818
DOI: 10.3389/fendo.2024.1378158 -
Frontiers in Veterinary Science 2024Raw diets have become popular in companion animal nutrition, but these diets may be contaminated with harmful bacteria because heat processing is not utilized to...
INTRODUCTION
Raw diets have become popular in companion animal nutrition, but these diets may be contaminated with harmful bacteria because heat processing is not utilized to mitigate pathogens during the production process. We analyzed 24 commercially available frozen raw canine and feline diets for extended-spectrum beta-lactamase-producing Enterobacterales (ESBL-E).
METHODS
Samples were incubated in tryptic soy broth augmented with 50 μg/mL ampicillin to enrich for ESBL-E. ESBL-E were isolated using CHROMagar ESBL plates and isolate identification and antibiotic susceptibility testing were confirmed using the VITEK2 instrument.
RESULTS
ESBL-E were isolated from 42% (10/24) of raw diets, with complex and predominating. Most ESBL-E isolates (71%, 32/45) were multidrug-resistant. Direct plating of samples onto tryptic soy agar yielded bacterial counts >6 log for 2 samples from two different manufacturers.
CONCLUSION
This preliminary study justifies further investigation into the potential contribution of raw diets to the dissemination of antibiotic resistant bacteria in companion animals and domestic living spaces.
PubMed: 38933698
DOI: 10.3389/fvets.2024.1294575 -
Frontiers in Pharmacology 2024() was widely used in poultry feeds. However, it is still unclear about how B.licheniformis regulates the growth and development of Pekin ducks. The experiment was...
() was widely used in poultry feeds. However, it is still unclear about how B.licheniformis regulates the growth and development of Pekin ducks. The experiment was designed to clarify the effect and molecular mechanism of on the lipid metabolism and developmental growth of Pekin ducks through multiomics analysis, including transcriptomic and metabolomic analyses. The results showed that compared with the control group, the addition of 400 mg/kg could significantly increase the body weight of Pekin ducks and the content of triglyceride (p < 0.05), at the same time, the addition of could affect the lipid metabolism of liver in Pekin ducks, and the addition of 400 mg/kg could significantly increase the content of lipoprotein lipase in liver of Pekin ducks. Transcriptomic analysis revealed that the addition of primarily impacted fatty acid and glutathione, amino acid metabolism, fatty acid degradation, as well as biosynthesis and elongation of unsaturated fatty acids. Metabolomic analysis indicated that primarily affected the regulation of glycerol phospholipids, fatty acids, and glycerol metabolites. Multiomics analysis demonstrated that the addition of B. licheniformis to the diet of Pekin ducks enhanced the regulation of enzymes involved in fat synthesis via the PPAR signaling pathway, actively participating in fat synthesis and fatty acid transport. We found that effectively influences fat content and lipid metabolism by modulating lipid metabolism-associated enzymes in the liver. Ultimately, this study contributes to our understanding of how can improve the growth performance of Pekin ducks, particularly in terms of fat deposition, thereby providing a theoretical foundation for its practical application. can increase the regulation of enzymes related to fat synthesis through PPAR signal pathway, and actively participate in liver fat synthesis and fatty acid transport, thus changing the lipid metabolism of Pekin ducks, mainly in the regulation of glycerol phospholipids, fatty acids and glycerol lipid metabolites.
PubMed: 38933681
DOI: 10.3389/fphar.2024.1412231 -
Frontiers in Physiology 2024Oleuropein, a phenolic compound derived from olives, has known glucoregulatory effects in mammalian models but effects in birds are unknown. We investigated effects of...
Oleuropein, a phenolic compound derived from olives, has known glucoregulatory effects in mammalian models but effects in birds are unknown. We investigated effects of dietary supplementation and exogenous administration of oleuropein on broiler chick feed intake and glucose homeostasis during the first 7 days post-hatch. One hundred and forty-eight day-of-hatch broiler chicks were randomly allocated to one of four dietary treatments with varying oleuropein concentrations (0, 250, 500, or 1,000 mg/kg). Body weight and breast muscle and liver weights were recorded on day 7. In the next experiment, chicks received intraperitoneal (IP) injections of oleuropein at doses of 0 (vehicle), 50, 100, or 200 mg/kg on day 4 post-hatch, with feed intake and blood glucose levels measured thereafter. Lastly, chicks fed a control diet were fasted and administered intracerebroventricular (ICV) injections of oleuropein at doses of 0, 50, 100, or 200 μg, after which feed intake was recorded. Results indicated that IP and ICV injections led to decreased feed intake, primarily at 60 min post-injection, with effects diminishing by 90 min in the IP study. Blood glucose levels decreased 1-h post-IP injection at higher oleuropein doses. These findings suggest that oleuropein acts as a mild appetite suppressant and influences energy metabolism in broiler chickens.
PubMed: 38933363
DOI: 10.3389/fphys.2024.1409211