3 Chapter 3: Supplements and Guidelines for Nutritious Diets

Nutrient Requirements and Intake Standards

Providing universal health recommendations and assessing the quality of diets requires understanding how much of each nutrient the body needs. The smallest quantity of a nutrient that sustains a particular level of nutritional health is known as a nutrient requirement. Age, sex, activity level, and life stage are some of the factors that affect these requirements, which have been established through years of scientific research and demographic studies.

U.S. health agencies created Dietary Reference Intakes (DRIs), a complete set of energy and nutrient intake requirements for healthy Americans, to address the nutrient needs of the entire population. These guidelines were set forth to:

• Lower the risk of nutrient deficiencies
• Prevent chronic disease
• Promote optimal health

DRI vs. RDA

DRI is an umbrella term for a number of distinct nutritional consumption values, such as:

• RDA (Recommended Dietary Allowance): Daily nutrient recommendations that meet the needs of 97–98% of healthy people in a life stage/sex group
• AI (Adequate Intake): Used when there is insufficient data to support an RDA. AI values are estimates based on observed intakes by healthy people.
• TUL (Tolerable Upper Intake Level): The maximum daily intake that most people can consume without posing the risk of experiencing negative health effects.
• ERR (Estimated Energy Requirement): Also known as Total Daily Energy Expenditure (TDEE), the average daily energy intake that meets the needs of a person who is maintaining their weight. It takes into account:
  • Body weight and height
  • Sex
  • Physical activity level
  • Age

There are many ERR or TDEE calculators freely available online to estimate the calorie intake of someone and the necessary adjustments needed to gain or lose weight. While these calculators can be moderately accurate because they consider the above metrics, they do not account for genetics, medical history, or nuances of individual metabolisms and lifestyles, which makes them prone to over- or underestimation.

Evaluating the Nutritional Profile of Foods

In an effort to help Americans meet their DRI, many food products are modified through enrichment or fortification:

• Enrichment is the process of restoring nutrients that were lost during processing (e.g., B vitamins in white flour).
• Fortification is the addition of nutrients that were not originally present in the food (e.g., vitamin D in milk or orange juice).

These tactics have been effective in lowering widespread nutrient deficiencies; however, relying too heavily on fortified products can overshadow the value of eating full, nutrient-dense foods.

Processed and Ultra-Processed Foods

Any food that has been modified from its original form for flavor, convenience, or preservation falls under the broad category of processed foods. Processing is quite common, with most foods undergoing at least minor processing such as washing, peeling, or packing. For example, freeze-dried berries, canned vegetables, pasteurized milk, baked bread, and candy bars are all examples of the various levels of processed foods. The notable demonized category is ultra-processed foods. They are distinguished by:

• Numerous added ingredients
• Chemical additives and flavor enhancers
• Low nutrient density
• Reduced fiber and water content

In the modern diet, these foods frequently replace whole, minimally processed foods. In 2019, a multi-year study with over 100,000 participants was published and found that every 10% increase in consumption of ultra-processed foods was associated with an approximate 12% higher risk for cancer ^[1].

In an RCT involving 20 overweight adults, participants were divided into two groups for the first two weeks, with one group consuming an ultra-processed diet while the other consumed a minimally processed diet ^[2]. Both groups received meals that were identical in terms of calories and macronutrient content. After two weeks, the groups switched diets. Participants were permitted to eat as much as they desired (ad libitum) during the trial, even though the nutrient profiles were controlled.

Researchers found:

• When consuming an ultra-processed diet, participants ate an extra 500 calories/day and gained ~1 lb./week
• When on the non-processed diet, participants lost ~1 lb./week
• Ultra-processed group ate more carbohydrates and fats

The study highlights the fact that ultra-processed foods may encourage overconsumption and are less satiating, most likely because they contain less fiber and water.

Supplements: When and Why?

Despite food enrichment and fortification, many Americans still lack certain essential nutrients. Iron, calcium, vitamin D, and omega-3 fatty acids are among the common deficiencies for many. Dietary supplements, products designed to “supplement” the diet rather than replace a healthy diet, have become widely used as a result.

Supplements are particularly relevant for:

• Older adults (vitamin B12, D, calcium)
• Pregnant people (folic acid, iron)
• Vegans/vegetarians (B12, iron, zinc, DHA)
• People with absorption disorders (celiac disease, Crohn’s)

Supplements should be used carefully. Supplement quality and potency can vary greatly, and the FDA does not monitor them as closely as it does pharmaceutical drugs. As mentioned last chapter, third-party testing and evidence-based use are vital for determining safety and accuracy.

The Rise of Meal Replacements

As lifestyles become busier, meal replacement goods, such as shakes, bars, or powders are becoming more popular. These often contain fiber, micronutrients, and balanced macronutrients and are promoted as handy, full substitutes for a traditional meal.

Pros:

• Time-saving
• Portion-controlled
• Nutritionally balanced if well-formulated

Cons:

• Lacks natural fiber or phytonutrients found in whole foods
• Could lead to an over-dependence on processed foods
• May not promote long-term healthy eating behaviors

The Evolution of Dietary Guidelines in the United States

The American government has been instrumental in influencing the public’s perception of healthy eating for more than a century. In an effort to help Americans satisfy their nutritional requirements and lessen the burden of nutritional diseases, federal agencies started issuing dietary guidelines in the early 20th century. Over time, these guidelines have evolved in response to new scientific findings, public health issues, and changes in the availability of food.

Timeline of American Dietary Guidelines:

• 1943: The Basic Seven – Developed during World War II, this guide stressed the need for variety but lacked portion control. E.g., one group, “butter and fortified margarine,” did not differ in portion recommendation from another group, “green and yellow vegetables”.
• 1956: The Basic Four – Revised the categories into milk, meats, fruits/vegetables, and breads/cereals. While simpler, the recommendations didn’t specify guidance on fats or sugar.
• 1992: The Food Pyramid – Introduced the infamous triangle diagram with serving recommendations that place grains at the base and fats and sugar at the top. This guideline emphasized to Americans to reduce their fat and sugar intake, but it did not differentiate types of fat and seemed to overemphasize the need for starchy carbohydrates.
• 2005: MyPyramid – Vertical bands were added to MyPyramid to customize nutrient requirements and indicate physical activity. The new bands helped reinforce vegetables and fruits as being important, but may have overemphasized milk and underemphasized overall protein.
• 2011: MyPlate – A plate icon replaced the pyramid and depicted food groups as portions of a plate split into four nearly identical quadrants, along with a cup of milk to the side. The four quadrants are fruits, grains, vegetables, and protein. A more detailed version of the guide was available, which specified what people should be eating for each portion.
• Harvard Healthy Eating Plate – Created by Harvard School of Public Health as an alternative to MyPlate, with more detailed recommendations on nutritious fats and food quality. This plate did not include a cup of milk and instead depicts a cup of water. Its illustration also has a larger portion for vegetables than fruit on one half of the plate and whole grains and healthy protein on the other half. Lastly, this plate has a picture of healthy oils and recommends limiting butter and avoiding trans fats.

The MyPlate Plan: Personalized Nutrition

The USDA introduced the MyPlate Plan to better personalize dietary recommendations to individual needs. Five factors are used by this tool to provide a customized eating guide:

• Age
• Sex
• Height
• Weight
• Physical activity level

These factors are very similar to the EER and TDEE calculators discussed last chapter. The algorithm provides 12 daily eating patterns, adhering to all food groups, with daily caloric values ranging from 1,000 to 3,200 kcal. The MyPlate Plan prepares 85% of the calories for a person within these patterns and is intended to satisfy almost all dietary requirements, with 15% remaining for flexibility, such as discretionary calories.

School Lunches and Nutritional Adequacy

The United States Department of Agriculture (USDA) is behind the creation of MyPlate and school lunch programs, which are aimed at providing nutrient-dense, well-balanced meals for American children, teenagers, and adolescents. Children’s daily nutrition is greatly influenced by school lunch programs, especially in low-income areas where they could be the most reliable source of food; therefore, adhering to school lunch program guidelines should theoretically satisfy the requirements for a healthy meal. Nevertheless, a number of criticisms have been made regarding the application and results of the school lunch program rules due to their looseness in interpreting some recommendations.

Criticisms include:

• Portions too small for active teenagers or too large for younger children
• Menu items with high levels of added sugar or sodium
• Over-reliance on ultra-processed foods (e.g., packaged fruit cups, flavored milk)
• Limited options for students with dietary restrictions (e.g., vegetarian, vegan, food allergies)

Looseness in the interpretation of healthy food recommendations includes a common practice of exploiting loopholes in how food components are classified. For example, apple or grape juice can be considered a full serving of fruit, even though it lacks the fiber and satiety advantages of whole apples and grapes, and a modest amount of tomato paste on pizza can be considered a vegetable serving. Fried potatoes could be considered a vegetable serving. Even with adherence to MyPlate (half the plate including fruits and vegetables), there could be meals that have French fries, a slice of pizza, and fruit juice that technically are considered compliant.

The issue of palatability and food waste is surely a driving factor in these choices. Flavor and overall taste are the main factors when it comes to food consumption among children and teens. School lunch programs also need to consider cost, prep time, and minimizing food waste. In this context, MyPlate provides an easy-to-use visual aid for school lunches, but implementing these recommendations in institutional contexts, such as school cafeterias, frequently puts compliance ahead of quality.

Enhancing school meals necessitates striking a careful balance between student preferences, financial restraints, nutritional requirements, and practical considerations. Nonetheless, higher-quality school meals have been repeatedly linked to improved academic achievement and a decreased risk of childhood obesity, so the need to continually improve the American Dietary Guidelines and decrease loopholes that undermine their intent still exists.