Day Seven - Nutrition Across the Lifespan

Our nutritional needs change throughout our lifespan.  Infants and children neednutrients to support their growing bodies and developing brains, while adolescents and adults need to focus more on maintenance than growth.  A pregnant or lactating woman needs to account nutritionally not only for her own needs, but for that of her baby, however she needs to be aware that "eating for two" does not mean "eating two servings of everything".

During pregnancy, a woman should focus on eating the most nutritious, healthy foods possible so the growing baby is able to absorb the nutrients it needs to develop normally.  In addition, pregnant women need to be sure they get enough vitamins and minerals to support the healthy development of the fetus, particularly Folic Acid, Calcium, and Vitamin D.  (Mayo Clinic, 2011)  Pregnant women need to maintain a healthy body weight both before and during pregnancy, since being either overweight or underweight can have negative consequences for the baby.

A growing infant requires more Vitamin D and Iodine proportionately than an adult in order to ensure proper development of bones and other systems.  Toddlers and school age children should be encouraged to eat a balanced diet so they will be more likely to make healthy food choices throughout their lives.  During the growth spurts of childhood and adolescence, the body's increased demand for Vitamin D and Iron must be accounted for in order to support strong bone growth and development. (Sizer & Whitney, 2011)

For adults, the focus needs to be on maintaining a balanced diet with the proper caloric intake in order to prevent the weight-related problems described earlier.  Older adults need to ensure they are getting adequate nutrition, as the amount of food eaten tends to decrease with age.  Overall, a lifetime of nutritious food choices will help stave off chronic diseases and contribute towards optimal health during the entire life span.

Reference:

Mayo Clinic (2011). Pregnancy Diet: Focus on these essential nutrients. Pregnancy Week By Week. Retrieved from http://www.mayoclinic.com/health/pregnancy-nutrition/PR00110

Sizer, F. & Whitney, E. (2011).  Nutrition Concepts & Controversies, 12^th Edition.  Belmont, CA: Wadsworth.

Day Six - Underweight, Overweight and Obesity

A healthy, balanced diet that consists of a variety of nutrient-rich foods will help prevent underweight, overweight, and obesity.  The diet must also provide the correct amount of calories for the individual in order to maintain a stable weight.  If a person eats fewer calories than he or she uses, he or she will lose weight as the body breaks down existing fat and muscle stores to survive.  Conversely, eating more calories than are used will result in weight gain as the body stores the extra calories as fat.

      Being outside of a healthy weight range has detrimental effects on the body, as the biochemical pathways are interrupted due to a lack of or overabundance of nutrients.  Being underweight will result in more short-term, acute effects as the body cannibalizes itself in order to scavenge enough calories to keep functioning.  The body also does not have any energy stores to fight against infection or disease, so the mortality rate for underweight people spikes dramatically as more weight is lost.  (Sizer & Whitney, 2011)

      Overweight and obesity tend to be more chronic problems, as the body is more able to store calories as fat for future use and does not have to immediately destroy itself to survive.  However, chronic excess fat storage – overweight or obesity – also disrupts the normal biochemical pathways, resulting in diseases such as diabetes and hypertension.  The extra weight also has a degenerative effect on joints and mobility, increased blood pressure can lead to kidney damage, and the excess circulating blood lipids contribute to cardiovascular disease and death.  (Wardlaw & Smith, 2006)

A nutritionally sound diet that contains the correct amount of calories is vital to preventing conditions and diseases associated with unhealthy weight.  Exercise in conjunction with a  proper diet will also help the body maintain a healthy weight.

References:

Sizer, F. & Whitney, E. (2011).  Nutrition Concepts & Controversies, 12^th Edition.  Belmont, CA: Wadsworth.

Wardlaw, G. & Smith, A. (2006).  Contemporary Nutrition, 6^th Edition.  New York, NY: McGraw Hill.

Day Five - The Digestive Process

The human body requires macronutrients such as fats, carbohydrates, and proteins to build and maintain itself, as well as sufficient quantities of vitamins, minerals, and water to make the biochemical processes of life possible.  The digestive system is a specialized gropu of organs that work together to extract these nutrients from the foods we eat.

Carbohydrate digestion begins in the mouth, where salivary amylase begins the process of breaking starches down into simpler sugars.  The mechanical action of chewing also helps with digestion by breaking down the cellular structure of the foodstuff and increasing the surface area over which digestive enzymes can access the food.

The stomach is a highly acidic pouch whose main purpose is to grind food into a paste called chyme.  The hydrochloric acid in the gastric juices helps break down proteins in the food into structures that can be absorbed in the intestines later on.  The stomach then releases the partially-digested food into the small intestine in small amounts, allowing the intestinal juices to continue the digestion and absorption of the nutrients.

The majority of nutrient absorption happens in the small intestine, which is a convoluted tube with corrugated walls.  Those walls are covered with tiny finger-like projections called villi.  This internal structure creates an immense amount of surface area over which nutrients can be absorbed by the body.  At the beginning of the small intestine, juices from the pancreas and liver are added to the chyme to reduce the acidity of the food that has come out of the stomach.  Bile is also added, which aids in the digestion of fats and lipids.  As the food passes through the small intestine, enzymes break the nutrients into molecules that can pass through the walls of the villi and into the bloodstream.

By the time food reaches the end of the small intestine, most of its nutritional elements have been removed.  What remains is passed into the large intestine, where excess water is reabsorbed by the body, along with some micronutrients that still remain.  The remaining undigested food is passed along the large intestine to the rectum to be excreted as feces.  (Sizer & Whitney, 2011)

While the body requires fats in order to function, different types of fats are metabolised and used differently.  Some, such as some plant oils like olive or vegetable oil, provide more benefit to the body because of how they bind and travel in the bloodstream.  These unsaturated fats are less likely to contribute to high cholesterol and heart disease.  Other fats, such as animal fats or mechanically-altered plant oils called trans fats, are more likely to result in heart disease.

Fiber plays a vital role in proper digestion and digestive health.  A high-fiber diet can reduce the amount of cholesterol absorbed in the gastrointestinal tract, reducing the level of cholesterol in the blood overall, and helping reduce the risk of heart disease.  (Chandalia, M., et al, 2000)  Fiber contributes to colon health by providing bulk to feces, as well as food to the microorganisms that live in a healthy large intestine.  Fiber also helps produce feelings of satiety, which helps reduce overall calorie intake and helps maintain a healthy weight.

References:

Chandalia, M., et al (2000). Beneficial Effects of High Dietary Fiber Intake In Patients With Type 2 Diabetes Mellitus.  New England Journal of Medicine.  Retrieved from http://www.nejm.org/doi/pdf/10.1056/NEJM200005113421903

Sizer, F. & Whitney, E. (2011).  Nutrition Concepts & Controversies, 12^th Edition.  Belmont, CA: Wadsworth.

Day Four - Dietary Guidelines

According to the U.S. Department of Health and Human Services, "A healthy diet can reduce the risk of major chronic diseases such as heart disease, diabetes, osteoporosis, and some cancers." (HHS, 2010)  In order to help Americans improve their ability to choose a healthy diet, the HHS developed Dietary Guidelines describing the amount of each nutrient the average American should try to eat.

The Guidelines provide ranges of caloric and nutrient intake for children, as well as for adult males and females, which demonstrates how those needs are affected by age and gender.  In general, for the average American adult, the macronutrient recommendations are:

• Protein: 10-35% of daily intake
• Carbohydrate: 45-65% of daily intake
• Fat: 20-35% of daily intake

The HHS also recommends that Americans increase their intake of whole grains, vegetables, and fruits; reduce intake of sugar-sweetened beverages; and monitor their calorie intake from alcoholic beverages.

Other recommendations from the HHS to help meet these guidelines include calorie control suggestions such as using smaller plates; tracking your daily intake in a food journal; replace portions of high-calorie foods with lower calorie foods such as vegetables and fruits; and experiment with ingredient substitution to create more healthy recipes when cooking.

The HHS has published a 112-page document that describes in detail the various nutrients, eating habits, calorie goals, and foods to either increase or reduce in the average diet. Overall the guidelines provide a lot of sound advice for individuals to follow, as well as a lot of information about how much of a given type fo food the average person should try to aim for.  Unfortunately at 112 pages long it is overwhelming for many people, and the "quick take-away points" that most people are looking for can be somewhat difficult to find or understand.

Reference:

U.S. Department of Health and Human Services (2010). Dietary Guidelines for Americans.  Retrieved from http://www.health.gov/dietaryguidelines/ 

Day Three - Food Choices and Factors

Several factors influence our food choices.  First and foremost is our family environment, including our heritage and culture, our socioeconomic status, and the eating habits of our parents.  Parents pass on their eating habits to their children, and children learn their eating preferences from the foods that are made available to them as they mature.  Families often have "favorite" meals that they serve during special occasions which may or may not be nutritionally healthy.  In the United States, holidays like Thanksgiving and Christmas revolve heavily around food, where the focus of the celebration is on the meal.  American society seems to accept that it is expected to over-gorge at these meals, which can distort the individual's idea of what a "correct" serving size is.

As children grow into adolescents, additional factors such as body image, time constraints, peer pressure, and increased independence can affect food choices.  A teenager who has access to a car and is working as well as going to school may be more likely to choose a fast food drive-through for a meal due to its convenience and affordability, rather than make a more healthy choice at home.  Time constraints for school or other commitments can have an effect on what an adolescent chooses to eat, which can have an effect on their overall health.  According to a study into the food habits of adolescents, "Omitting breakfast was an important indicator of less healthy lifestyle and a food choice leading to a poorer nutrient intake." (Sjoberg, 2003, pg 1578)

Philosophical choices can have a strong influence on what we choose to eat, and can have serious ramifications if nutritial deficiencies are not taken into account.  Vegetarians and vegans, for example, must find alternate sources of protein to provide their bodies with the essential amino acids for the healthy functioning of many organ systems.

Reference:

Sjoberg, A., Halberg, L., Hoglund, D., & Hulthein, L. (2003). Meal pattern, food choice, nutrient intake and lifestyle factors in the goteborg adolescence study. European Journal of Clinical Nutrition, 57(12), 1569-78. doi: 10.1038/sj.ejcn.1601726

Dissertations and Theses, , n/a. Retrieved from http://search.proquest.com/docview/304734259?accountid=32521. (304734259).

Day Two - The Healthy Diet

A healthy diet is one that provides ample, quality nutrients through a variety of foods, designed to provide the body with the nutrition it requires.  According to the National Institutes of Health, "Good nutrition means your body is getting all the nutrients, vitamins, and minerals it needs to work at its best level. Eating a healthy diet is your main way to get good nutrition."  (NIH, n.d.)  A healthy diet also takes into account the activity level and life stage of the individual, since nutrient and caloric needs change over time.  An infant or toddler has different nutritional requirements than an adult or senior citizen, and a high school football player has different caloric requirements than a middle-aged secretary.  Lifestyle and life stage are important to consider when choosing the right foods.

A healthy diet will include foods that contain all six nutrient groups: protein, carbohydrates, fat, vitamins, minerals, and water.  Proper amounts of these nutrients will enable the body to maintain itself, to fight disease, to grow and replace worn-out tissue, and to stay in the correct balance.

Since our needs change over time, one of the biggest challenges to choosing a healthy is knowing “what do I need right now?”  An infant or toddler needs foods that will provide the nutrients for growth and development.  The football player will require more protein to help build muscle and carbohydrate for energy while on the field.  An elderly person will not require as many calories, however they need to ensure that the foods they do eat are nutrient-dense in order to provide their bodies with the ability to fight illness and stave off the deterioration of their tissues.  A middle-aged secretary needs to ensure she doesn’t take in too many calories to prevent overweight or obesity, as well as make sure she is eating enough vitamins and minerals to help prevent diseases like osteoporosis.

The key to knowing “what do I need right now?” is education.  Understanding what part proteins, carbohydrates, fats, vitamins, minerals, and water play in the complex biochemistry that is the human body – even if it is just on a surface level – is important to understanding how to select foods that will give your body what it needs to operate most efficiently.  For example, if someone understands that most processed foods add salt and fat while removing fiber and nutrients, and why that is bad for their body, it can encourage them choose more nutritious foods instead.

Reference:

National Institutes of Health (n.d.).  Diet and Nutrition.  Retrieved from: http://www.nichd.nih.gov/health/topics/Diet_and_Nutrition.cfm

Day One - Nutrition and Disease

Nutrition is something that affects everyone, every day, whether we realize it or not.  The food we eat is what our bodies use to repair, rebuild, and refuel, and in order to keep our bodies functioning at their best, we have to be sure to provide it with the right nutrients.  Proper nutrition gives our bodies the ability to carry out the countless biochemical reactions it has to perform every day, from building tissue and healing wounds to more complex interactions like fighting disease.

Our bodies require a balance of nutrients in order to have the right components to work.  An imbalance in those nutrients can create a deficiency in a vital component needed to function, which in turn can affect numerous systems in the body.  A deficiency of calcium, for example, affects not only the formation of bone, but also affects the body's blood clotting ability, which in turn can contribute to bleeding disorders. (Thibodeau & Patton, 1997)

Improper nutrition can also set the body up for disease.  Malnutrition makes a person more susceptible to diseases such as infections, since the body’s immune system is weakened due to lack of nutrients.  It also slows wound healing and tissue generation since the body does not have enough of the raw materials needed to repair itself.  Malnutrition can cause a person’s body to turn against itself and begin breaking down organs and muscles in an attempt to find the nutrients it needs, which often results in death.

On the other side of the scale, obesity is also the result of inappropriate nutrition.  In this case, a person takes in more calories than they use on a regular basis, and the body takes the extra calories and stores them for later usage.  Many of these extra calories are stored as fat, which increases a person’s weight.  These extra calories and the increase in weight can affect many systems in the body, causing chronic diseases such as hypertension (high blood pressure), insulin resistance and diabetes, arthritis, kidney failure, cardiovascular disease, and even some cancers.  (Sizer & Whitney, 2011)  Of the leading causes of death in the United States, the top three can be associated with poor nutrition.

Nutrition plays a key role in health and disease, and a balanced diet that is high in nutrients while reasonable in calories is the first step towards preventing the onset of chronic illness.

Reference:

Sizer, F. & Whitney, E. (2011).  Nutrition Concepts & Controversies, 12^th Edition.  Belmont, CA: Wadsworth.

Thibodeau, G. & Patton, K. (1997). The Human Body in Health & Disease, 2^nd Edition.  St. Louis, MO: Mosby.