NS 1150 Prelim 1

What are dietary guidelines?

Science-based advice on what to eat and drink to promote health, reduce risk of chronic disease, and meet nutrient needs.

Are dietary guidelines mandatory?

No, they are not lawful, not enforced, and not mandatory. However, they do form the basis of Federal Nutrition Policy and programs

What historical diet contributed to scurvy among sailors?

The 18th century British Naval Diet included salt beef, ship's biscuit, oatmeal, sugar, cheese, beans, and grog.

What was the average caloric intake of the British Royal Navy in the 18th century?

Approximately 5000 calories per day.

What are common symptoms of scurvy?

Bruising, slow healing wounds, bleeding gums, loosening of teeth, muscle pain, joint pain, fatigue, fever, convulsions, and death.

How many sailors died from scurvy between the 16th and 18th centuries?

Scurvy was responsible for more than 2 million deaths among sailors.

What was the fate of Vasco da Gama's crew during his first voyage to India?

He lost 116 of 170 men (68%) mostly to scurvy. (1499)

What was the outcome of Commodore George Anson's circumnavigation trip?

He lost 1,666 of 1,854 men (90%) mostly due to scurvy. (1744)

What ineffective treatments were used for scurvy?

Sulfuric acid, blood-letting (venesection), and drinking seawater.

What effective (some) treatments for scurvy were identified?

Eating rats, scurvy grass (Cochlearia officinalis), and citrus fruits.

Who conducted the first recorded randomized controlled trial for scurvy?

James Lind in 1747 on HMS Salisbury (boat).

What was the most effective treatment found by James Lind for scurvy?

Two oranges and one lemon a day.

What challenges did James Lind face in disseminating his findings?

Poor documentation, lack of influence, poor dissemination of Navy/wider public, and no practical dietary guidelines implemented. No one acted on his results!

Sir Gilbert Blane (1749-1834)

Physician in the Royal Navy. He reproduced James Lind's study (used alcohol to preserve lemon juice) and recommended findings to the Admiralty,

What did the Royal Navy mandate in 1795 regarding citrus consumption?

Daily consumption of lemon juice by every sailor, added to grog.

How much citrus juice was needed annually for the Royal Navy?

50,000 gallons of citrus juice per year.

What is Lesson 1 regarding nutrition and disease?

Nutritional imbalance/inadequacy can lead to major health impacts. Modern examples: obesity and type 2 diabetes.

What is Lesson 2 about dietary guidelines?

Scientific evidence underpins dietary guidelines.

What are the three types of biomedical research?

Basic, preclinical, and clinical research.

What is basic biomedical research?

Seek knowledge into fundamental properties and behavior of life molecules. (molecules, cell models, animal models.

What is clinical biomedical research?

Human studies to dissect characteristics of disease or trial an intervention.

- Observational: case-series, case control (retrospective, and cohort (prospective)

- Experimental: controlled trials, randomized controlled trials

What is pre-clinical biomedical research?

Animal models to test effect of intervention e.g., therapeutic drug/strategy. (Cell models, animal models)

What modern examples illustrate the impact of food choice on the society and economy?

High beef and milk consumption impacts economic decisions and environmental consequences. Choice of land use e.g., loss of rainforest. Fishing rights, trade agreements, disputes over international waters... war!?

What is the primary purpose dietary guidelines?

To promote health through meeting nutritional demands.

What lessons did we learn from the history of scurvy?

Research needed to identify dietary cause as a causal factor and as a treatment.

Critically analyze and communicate the research in the form of recommendations/ guidelines.

Implement the guideline as practical nutritional policy.

Benefits and challenges of implementing a successful policy

What nutrient is identified as the active component against scurvy?

Vitamin C (ascorbic acid).

What is the function of Vitamin C?

Acts as an essential co-factor for enzymes involved in collagen synthesis.

Which enzymes require Vitamin C for collagen synthesis?

Prolyl-hydroxylase and lysyl-hydroxylase.

What role do hydroxyl groups play in collagen structure?

They allow collagen peptides to crosslink into a triple-peptide helix, providing tensile strength.

What are the consequences of Vitamin C deficiency?

Weak collagen leading to breakdown of connective tissue in skin, muscle, joints, and gum, resulting in symptoms of scurvy.

Why can't humans (and guinea pigs)synthesize their own Vitamin C?

They lack the enzyme GULO (L-Gulonolactone oxidase) required for Vitamin C synthesis.

Which animals can synthesize their own Vitamin C?

Other mammals, including rats. Therefore, can survive a long voyage unaffected by scurvy. However, cooking the meat will destroy the animals vitamin C content.

What factors contribute to Vitamin C deficiency in modern times?

Intake deficiency: Socio-economic factors (social isolation/nutrient insecurity), behavioral issues (alcohol/infant feeding practices), pathology (allergy/eating disorders).

Malabsorption: Inflammatory bowel disease, bariatric surgery.

Increased consumption: smoking

Increased excretion: kidney disease

How can dietary guidelines help prevent Vitamin C deficiency?

By providing recommendations for adequate intake and addressing barriers to access.

What challenges exist in implementing dietary guidelines?

Human nature doesn't change and resistance to change, such as reluctance to switch from coffee to tea.

What is the role of the Food and Nutrition Board (FNB)?

To provide leadership in nutrition and food science and advise on nutrition and food policy.

When was the Food and Nutrition Board established?

In 1940.

What are the primary functions of the Food and Nutrition Board?

To explore safety and adequacy in the food supply and establish principles and guidelines for good nutrition.

What is a significant challenge in translating scientific evidence into dietary guidelines?

The need for multiple independent studies to reach a general consensus.

Why might not everyone benefit from dietary recommendations like coffee or tea consumption?

Some individuals may experience health detriments from drinking coffee or tea.

What is one proposed dietary recommendation based on population studies?

To recommend 1.8 cups of coffee/tea per day.

What is the importance of understanding the physiological function of Vitamin C in dietary guidelines?

It highlights the need to ensure adequate intake and reduce the risk of deficiency.

What are the implications of social, economic, and medical factors on dietary guidelines?

They can reduce the efficacy of dietary guidelines.

What is the significance of establishing a national food fortification policy?

To ensure adequate nutrient intake across populations.

What happens if there is over-supplementation of Vitamin C?

It can lead to adverse health effects.

What are Dietary Reference Intakes (DRI)?

Documents issued by the Food and Nutrition Board that provide information on the basic function of nutrients, food sources, and effects of deficiencies and excessive intakes.

What is the purpose of DRI?

To offer quantitative estimates of nutrient intake necessary to maintain health in the US and Canada, addressing safety, quality, and adequacy of the food supply.

What does Estimated Average Requirement (EAR) represent?

The average daily level of intake estimated to meet the requirements of 50% of healthy individuals, used to calculate the Recommended Dietary Allowance (RDA).

What is the Recommended Dietary Allowance (RDA)?

The average daily level of intake sufficient to meet the nutrient requirements of nearly all (97-98%) healthy individuals, often used for planning nutritionally adequate diets for individuals.

What is the Tolerable Upper Intake Level (UL)?

The maximum daily intake unlikely to cause adverse health effects; it is not intended as a recommended level and does not provide established benefits for healthy individuals.

What does Adequate Intake (AI) signify?

The intake level assumed to ensure nutritional adequacy, established when there is insufficient evidence to develop an RDA.

How do DRI reference values vary?

They vary by age and sex, with specific life stage groups defined.

List the life stage groups for DRI.

Infancy (0-6 months, 7-12 months), Toddler (1-3 years), Early childhood (4-8 years), Puberty/Adolescence (9-13 years, 14-18 years), Young Adulthood and Middle Ages (19-30 years, 31-50 years), Adulthood and older adults (51-70 years, >70 years), Pregnancy and Lactation.

What is the role of Dietary Guidelines for America (DGA)?

To provide recommendations on food and drink to meet nutrient needs, promote health, and prevent disease, updated every 5 years based on the best available evidence.

How does DGA utilize DRI?

DGA uses DRI to assess the benefits and risks associated with nutrient intake.

What is a dietary pattern?

The combination of foods and beverages that make up an individual's complete dietary intake over time, aimed at promoting positive health outcomes.

What are the three parts of a dietary pattern?

1. Nutrient Dense Foods: High in macro/micronutrients per weight. 2. Avoid Excess Calories: Prevents obesity by focusing on nutrient-dense foods with fewer calories. Portion size important 3. Limit salt/sugar/fat:

What is the significance of nutrient-dense foods in a dietary pattern?

They contain high levels of nutrients relative to their weight and lower amounts of saturated fat, sugar, and salt.

Why is it important to avoid excess calories?

Excess calories can lead to obesity, making it crucial to focus on nutrient-dense foods that contain fewer calories.

What does the DGA emphasize about dietary patterns?

It emphasizes the big picture of what individuals eat regularly, rather than just fulfilling daily recommended allowances.

What is the goal of educating the public about nutrition?

To empower individuals to eat a balanced and healthy diet while minimizing the medicalization of nutrition.

How often are the Dietary Guidelines for America updated?

Every 5 years.

What is the relationship between diet, lifestyle, and health according to the DGA?

The DGA corroborates the correlation between diet, lifestyle, and health based on evidence from peer-reviewed journals.

What is the importance of reviewing science in developing new guidelines?

It ensures that the guidelines are based on the best available evidence, promoting public health.

What health issues are associated with excess salt consumption?

Hypertension, cardiovascular disease, and kidney disease.

What health issues are linked to excessive sugar intake?

Obesity, cardiovascular disease, type 2 diabetes, and tooth decay.

What are the consequences of consuming too much saturated fat?

Obesity, cardiovascular disease, metabolic liver disease, pancreatitis, and cancer.

What are some strategies to avoid excess salt, sugar, and fat in the diet?

Choose nutrient-dense foods, read nutrition labels, use salt/sugar alternatives, implement policies in institutions e.g., schools, hospitals, workplaces.

Individualized dietary pattern

- choice of ingredients and preparation method. - cultural bachground can have impact on food and beverage choice. - budgetary constraints. - different food groups (fresh, canned, dried). portion size important to meet calorie needs.- individual preferences

What is food fortification?

The practice of deliberately increasing the content of micronutrients (i.e. vitamins and minerals) in food to improve nutritional quality and provide public health benefits.

What are the advantages of food fortification?

HEALTH: very effective public health method to prevent nutriontional deficiencies

ECONOMIC: Significant healthcare and productivity savings from prevention of nutrion-related diseases

SOCIAL: Ensures equal access to safe and nutritious food within society

What are some disadvantages of food fortification?

HEALTH: Can delay diagnosis of pathology by masking symptoms of nutrient deficiency. Also concern regarding exceeding tolerable upper intake level (UL).

ECONOMIC: Sourcing and importing fortified food may be expensive.

SOCIAL: Need cooperation and trust between public, government and private sector.

What is universal salt iodization?

A WHO recommendation to fortify salt with iodine to prevent iodine deficiency.

What was the impact of iodine fortification in the 1920s?

Significant decline in the incidence of goitre and hypothyroidism.

Why is vitamin D important, and how was it addressed in the 1930s?

Vitamin D is required for calcium absorption; fortification in milk was recommended to reduce deficiency.

What are the consequences of vitamin D deficiency?

Osteomalacia in adults and rickets in children, leading to decalcification of bones.

What was the purpose of folic acid fortification in the 1990s?

To prevent folic acid deficiency during pregnancy, which can negatively impact fetal development.

What condition can result from folic acid deficiency during pregnancy?

Spina bifida, leading to lifelong disability.

What is point-of-use fortification?

Adding vitamins and minerals to foods just before consumption at home or in institutions.

How can cultural background influence dietary choices?

It can significantly impact food and beverage preferences.

What should dietary patterns consider besides health?

Budgetary constraints and individual/family preferences.

What is the role of nutrition labels in dietary choices?

They help consumers make informed decisions about salt, sugar, and fat content.

What are micronutrient powders used for?

Point-of-use fortification of foods for infants and young children.

What is the significance of variety in food choices?

Incorporating different food groups and options like fresh, frozen, dried, and canned foods.

What is the role of policies in institutions regarding nutrition?

To promote healthier food choices in schools, hospitals, and workplaces.

How does the FDA influence vitamin D fortification?

The FDA recommended (but did not mandate) vitamin D fortification in milk.

What is the relationship between nutrient deficiencies and public health?

Preventing deficiencies through fortification can lead to significant public health benefits.

What is the importance of individualized dietary patterns?

They ensure that dietary choices align with personal health needs and preferences.

What year did the US government launch folic acid fortification in grain products?

1998

What is the estimated number of babies that folic acid fortification is expected to prevent from spina bifida and related defects each year?

1300 babies

What do the Dietary Guidelines for Americans promote?

Healthy dietary patterns to maintain health and reduce the risk of chronic disease.

What are the key focuses of a dietary pattern according to the guidelines?

Nutrient-dense foods, avoiding excess calories, and limiting intake of salt, sugar, and saturated fat.

What factors should dietary patterns be individualized based on?

Culture, lifestyle, age, budget, and other life factors.

What is the purpose of national fortification policies?

To supplement additional nutrients to food and prevent nutritional deficiencies.

What are the four methods of nutritional assessment?

Dietary assessments, clinical assessments, anthropometric assessments, and biochemical assessments.

Why is nutritional assessment important?

To identify nutritional status and nutrition-related diseases, to determine appropriate nutrition therapy or programs, and to assess response to nutrition/medical therapy programs.

What is a 24-hour recall in dietary assessment?

A method that collects detailed information about food and beverages consumed in the past 24 hours.

What are some pros of using a 24-hour recall for dietary assessment?

Intake can be quantified and it is easy to complete.

What are some cons of using a 24-hour recall for dietary assessment?

It relies on recall (short-term memory) and may require multiple recalls to capture habitual intake.

What does a Food Frequency Questionnaire (FFQ) assess?

How frequently certain food and beverage items are consumed over a specific extended period of time (typically 3 months to 1 year). Focuses on consumption patterns and habitual intake.