Food Guidelines Evolution and DRI Standards

Food Guidelines Evolution

• Food guidelines have evolved since 2007, shifting to emphasize a wider variety of foods from each food group.
• A key concept is the "dilution effect," suggesting a mix of foods reduces negative impacts.
• Moderation in fat, sugar, salt, and calorie intake is crucial for balanced diets.
• Proportions and balance are emphasized in contemporary dietary advice.

Dietary Reference Intakes (DRI)

• DRI is a broad term for USA and Canada's dietary standards.
• It comprises the Estimated Average Requirement (EAR), Recommended Dietary Allowance (RDA), Adequate Intake (AI), and Tolerable Upper Intake Levels (UL).

Current Dietary Concerns

• Processed foods make up a significant portion (60%) of the US diet.
• Metabolically healthy adults in the US are a minority.
• Obesity rates are high, with 42% of adults and 19% of children obese.
• Diabetes and pre-diabetes affect half of US adults.
• Chronic diseases are rising in younger generations.
• Global deficiencies exist in iron, Vitamin E, and calcium.
• Portion sizes have increased dramatically over the past 40 years.

Fats and Lipids

Types of Fats

• Saturated Fatty Acids:
  • Solid at room temperature.
  • High in hydrogen content.
  • Examples include whole milk and coconut oil.
• Monounsaturated Fatty Acids:
  • One double bond.
  • Includes omega-9.
  • Common in olive oil and canola oil.
  • Polyunsaturated Fatty Acids:
  • Multiple double bonds.
  • Include essential fatty acids (Omega-3 and Omega-6)
  • Found in sunflower oil and fish.

Trans Fats

• Created through hydrogenation.
  • Naturally occurring in dairy (4-6%).
  • Commonly found in processed foods and margarines.
  • Artificial trans fats have health concerns.

Fat Digestion Process

• Mechanical breakdown begins in the mouth.
• Emulsification occurs.
• Pancreatic lipase plays a role in fat breakdown.
• Bile acids are involved in fat digestion.
• Fats are absorbed into the lymphatic system.
• Approximately 97% of bile acids are recycled.

Lipoproteins and Fat Metabolism

• Lipoproteins (e.g., HDL, LDL) transport fats through the bloodstream.
• High-density lipoproteins (HDL) transport excess cholesterol back to the liver.
• Maintaining healthy cholesterol levels is important for good health.

Role of Fats

• Fats provide energy (9 kcal/gram).
• Fat protects organs.
• Fats are an energy reserve.
• Fats are precursors to eicosanoids, phospholipids, bile acids, and steroid hormones.

Fat Sources in Foods

• High-fat foods include donuts, butter, and fatty meats.
• Moderate-fat foods include milk products.
• Whole-grain products are considered low-fat.
• Oil composition varies, with olive oil being primarily monounsaturated, coconut oil saturated, canola oil monounsaturated, and sunflower oil polyunsaturated.