Lecture 24 - Other Specialty Diets

what prompted people to start doing a Mediterranean diet

Epidemiological studies report increased longevity and reduced morbidity in Mediterranean countries versus North America & Northern Europe

Attributed to dietary pattern

Adherence to these dietary patterns has started to decline as these nations have westernized (increasing prevalence of obesity)

what is the Mediterranean diet

not so much a specific diet but a dietary pattern

High consumption of plant-based foods (e.g. fruits, vegetables, legumes, nuts, etc.)

Seasonally fresh and locally grown foods

Extra virgin olive oil as the primary source of dietary lipid

Moderate intake of wine (red)

Fresh fish & seafood, Low consumption of red and processed meat

Moderate consumption of dairy products, poultry, & eggs

what makes the Mediterranean diet healthy

Quality of fat (diet is low in saturated and trans fats, but high in monounsaturated fats)

Diet may increase satiety (still debated whether fat is more satiating than carbs)

High use of olive oil and legumes enhances palatability of the diet (increased consumption of foods high in dietary fibre and low in energy density)

Diets rich in monounsaturated fat improve glucose homeostasis (important in obesity/type 2 diabetes)

what is gluten

family of proteins found within grains (e.g. wheat, rye, barley)

Present in the endosperm (gliadins and glutenins)

• Only gliadins have been linked to celiac disease

what are gliadins

Gliadins are alcohol soluble proteins rich in glutamine and proline

4 types of gliadins (⍺, β, g, w), with ⍺-gliadins thought to be the most damaging

what is the gluten free diet

Gluten-free dieting is simply restricting the consumption of food products containing gluten

what are examples of gluten subsitutes

Corn, Rice, Oats (often contaminated with gluten), Quinoa, Amaranth, Sorghum, Flax, Chickpeas

when is the gluten free diet used

Celiac Disease (CD, chronic inflammatory bowel disease triggered by gluten)

Non-celiac gluten/wheat sensitivity (NCGS)

Wheat allergy

what is the pathogenesis of celiac disease

Exposure to immunogenic gliadin peptides leads to a cascade of changes in both the surface epithelium and lamina propria through immune-mediated mechanisms (innate & adaptive)

Increased IL-15 increases recruitment of cytotoxic intraepithelial lymphocytes

Gliadin becomes more immunogenic once it reaches the lamina propria and is deaminated by tissue transglutaminase

how is celiac disease diagnosed

Positive Celiac Disease-specific serology

Small bowel biopsy specimens with characteristic histological features

Positive response to a gluten-free diet

is the gluten free diet associated with weight loss

While some individuals may experience weight loss due to a reduced caloric intake or elimination of highly processed foods, the gluten-free diet is not inherently a weight loss diet and can also lead to weight gain if high-calorie gluten-free products are consumed.

is the gluten associated with heart disease

increased consumption in diet associated with reduction in heart disease

what is intermittent fasting

Voluntary abstinence from food & drink

Many different forms

Striking evidence in preclinical studies suggests that intermittent fasting has numerous health benefits

what is complete alternate day fasting

involves alternating fasting days (no energy containing foods or beverages consumed) with eating days (foods and beverages consumed ad libitum)

what are modified fasting regimens

allows consumption of 20-25% of energy needs on scheduled fasting days; the basis for the popular 5:2 diet, which involves severe energy restriction for 2 nonconsecutive days per week and ad libitum eating for the other 5 days

what is time restricted feeding

allows ad libitum energy intake within specific time frames, including regular, extended fasting intervals; studies of < 3 meals per day are indirect examinations of a prolonged daily or nightly fasting period

what are the metabolic benefits associated with alternate-day fasting

When combined with exercise, alternate day fasting improved insulin sensitivity and decreased liver fat accumulation

what are potential benefits associated with intermittent fasting

Better synchronization of your body’s inherent circadian cycles/rhythms (time-restricted feeding)

Optimized gut microbiome profiles

Improved metabolic homeostasis

• Decreased circulating lipids, Decreased inflammation, Decreased circulating insulin and enhanced insulin sensitivity

Intermittent fasting may promote weight loss and improve metabolic health through altering gut microbiota metabolism and subsequent browning of adipose tissue