Lipids: The Basics

Now it’s time for the good stuff, fats! Fats (or lipids) have a reputation of being bad for the body, but tasting too yummy to resist. Everyone seems to know the downside to eating too much fat; for example, the increased risk of cardiovascular disease and, of course, weight gain. However, lipids do benefit the body. For instance, fats:

1.     Are energy reserves

2.     Provide padding around the vital organs

3.     Serve as a temperature buffer

4.     Majorly compose cell membranes (phospholipids)

5.     Transport fat-soluble vitamins and nutrients

There are several types of lipids: triglycerides, phospholipids, and sterols.

        Triglycerides are three fatty acid chains attached to a glycerol molecule. Which is just some chemistry talk to say that the molecule looks like a stick with three streamers hanging off of the side. The term “fat” actually refers to the term “triglycerides”. A triglyceride is the storage form of fat. The non-stored version of fats is the separate fatty acid chains and glycerol molecule floating in blood; they are long chains of carbon, oxygen, and hydrogens. Fatty acids differ from each other in chain length or types of bonds between carbon atoms. A saturated fatty acid is a chain with only single bonds between the carbons; put in another way, it is completely saturated with hydrogen atoms. Because their packed together tightly with single bonds they are solid at room temperature. Examples of foods with a high saturated fat content are:

• Butter
• Cheese
• Nuts
• Processed meat
• Animal fats

Unsaturated refers to fatty acid chains with double bonds between some of the carbons. Because some carbons have two bonds with each other, they have fewer chances to bond with hydrogen atoms. This causes a lower saturation of hydrogens and, due to the loosely packed double bonded chains; they are liquids at room temperature. The locations in the chain without hydrogens are referred to as points of unsaturation. Depending on how many points there are decides how an unsaturated fatty acid is named. A fatty acid with one point of unsaturation is referred to as a monounsaturated fatty acid and if it has two or more double bonds it is called a polyunsaturated fatty acid (which have different names depending on where the double bonds are; ex: omega-3 fatty acid and omega-6 fatty acid). Examples of unsaturated fats include:

Monounsaturated	Polyunsaturated
peanut butter	fish
olives	flaxseed
avocados	walnuts
olive oil	soymilk
sunflower oil	corn oil

The last kind of fatty acid is called trans fats. Usually, in a polyunsaturated fat, the hydrogens that bond with the carbon atoms are on the same side of the chain. In trans fats, one of the hydrogen atoms switches sides, resulting in the hydrogens being on opposite sides. Some trans fats occur naturally, and depending on how much you eat, they have a little effect on the body; however, synthesized trans-fatty acids behave somewhat like saturated fats in the body. Examples of food with trans fats are:

• French fries
• Twinkie
• Margarine
• Pancakes
• Fried chicken

In general, saturated fat is known as the “bad” fat and unsaturated fat is known to be “good”. But the truth is that both fats are necessary in the diet and beneficial to the body. The stereotype of “bad” and “good” comes from the idea that saturated fats are easier to overindulge in and, therefore, contribute more to weight gain. When selecting foods it is important to consider that even though unsaturated fat may be healthier, eating too much is still not healthy.

A phospholipid molecule is similar to a triglyceride, but instead of three fatty acid chains it only has two. Instead of a third chain it has a molecule that makes the phospholipid water soluble; therefore, these molecules have hydrophobic and hydrophilic (the fatty acid chains are fat soluble) portions. Phospholipids arrange themselves tightly to become the cell membrane; and because of their water-loving and fat-loving components, vitamins and hormones may easily enter the cell. Another function of phospholipids is to behave as an emulsifier (mixing fats in water).

Sterols are molecules composed of several ring like structures. An example of a sterol is cholesterol. Although cholesterol is best known for causing plaque to collect in the arteries (a disorder called atherosclerosis) which can lead to more serious conditions such as heart attacks and strokes, it is important to the body. For instance, cholesterol serves as the basis for:

• Bile acids
• Steroid hormones
• Vitamin D

and is a fundamental element for cell membranes.

There are several forms of lipoproteins that carry fats, they are very-low-density lipoproteins (VLDL), low-density lipoproteins (LDL), and high-density lipoproteins (HDL). A VLDL carries mainly triglycerides to cells in the body to be used. Once a VLDL has donated its triglyceride molecules it becomes an LDL which hands out cholesterol to an accepting body tissue. HDL carries cholesterol from the body cells back to the liver to be disposed. Typically, LDL is known as the “bad” cholesterol and HDL is known as “good”; but it’s important to keep in mind that these lipoproteins are carrying the same cholesterol compound; the difference is where they are taking the sterol. Both are important for normal body function, it can become troublesome when there is a lot of cholesterol that can be given out to the body cells. This doesn’t make LDL “bad”, it just makes it easier to be affected by unhealthy eating habits.

The take home message of this post is that fats are beneficial in moderation.  

• Hannah

Glycemic Index for Athletes

Now that we have learned the basics of carbs and how our body can use them we can move forward to see how athletes can use the knowledge of carbs and their glycemic effect to gain the best performance. You may be asking what is glycemic index, and it’s how fast or how high the carbohydrate filled food we eat will be used to raise glucose in the blood. So, in other terms, how fast will we feel the food through energy. We all have felt the effects of eating a high sugary food - like donut - and then we crash, compared to oatmeal, which can sustain energy for a longer amount of time because it contains long chain starches and fiber. Now the donut creates a fast and high glycemic reaction, but will not stay at that level and that's when we have a drop. While the oatmeal is absorbed slower through more process due to the long chain fibers and starches. For athletes this is important because to fuel the body for a long term activity like a soccer match or a big mileage run requires a lower glycemic index food that will sustain the energy and not create the fall in energy. You would think the food with higher glycemic index would be better, but the index is made through the amount of simple sugars (monosaccharides), which learn about in the previous post; simple sugars are digested fast.  We see a slow release of glucose from the low glycemic index foods and a fast release of glucose in the high glycemic foods. 

Food with HIGH glycemic index:

• sports drinks
• white bread
• watermelon (fruits with high water and sugar content)
• candy

Foods with a LOW glycemic index:

• plain yogurt
• beans/lentils
• banana/apple
• whole grains

Now it may sound like that low glycemic foods would be the better option, but a quick absorption of the high glycemic index foods are also needed during activity or competition. Sports drinks and fruit especially are important during half time break, they give a quick burst of energy when the athletes need it the most and to keep going. A balance of everything is important, and timing with our foods especially for athletes is important to find. I know for myself that before long run, the day before I hunker down with the sustaining carbs and so the morning of I can simple drink some gatorade and graham crackers. Yes, I know it seems like a weird combination, but it's something and doesn’t upset my stomach. The morning fast glycemic food give me a “wake-up” energy but the food from the day before give the bulk of my energy I need for the whole time. Athletes need to find their niche and understand the a low and high glycemic index, when it comes to their performance level.

- Sara

References

Wein, D. (n.d.). Glycemic Index For Athletes. NSCA’s Performance Training Journal,6(3), 14-15. Retrieved September 17, 2015, from http://athletics.macalester.edu/custompages/Deno_Videos/nutrition/glycemic_index.pdf

Clark, N. (2014). Carbohydrate: Simplifying a Complex Topic. In Nancy Clarks' Sports Nutrition Guidebook (5th ed., pp. 111 - 135). Newton, MA: Sports Nutrition Services.

Carbohydrates: The Basics

Carbohydrates are defined as compounds made of one or many sugars. We all love them for their taste but we need them because they are best source of energy for the body to fuel muscles and they promote good health. In this post, I’ll address the basics about carbohydrates and debunk some myths about their value to our diets.

There are two forms of sugars that compose simple carbohydrates, they are monosaccharides and disaccharides. Monosaccharides are single sugar units. There are three types of monosaccharides called glucose, fructose, and galactose. Disaccharides are two sugars linked together. There are three types of disaccharides called:

• maltose (glucose + glucose)
• sucrose (fructose + glucose)
• lactose (galactose + glucose)

Simple carbohydrates are absorbed by the body fairly easily because they do not require much work (or any work in the case of monosaccharides) to be broken down into small enough pieces to be drawn into the bloodstream.

Complex carbohydrates (like fiber, glycogen, and starch) are also known as polysaccharides. A polysaccharide is a very long chain of sugars; because the link is so long, it must be broken down into smaller components (monosaccharides) before the body can absorb them. This means that complex carbohydrates are absorbed slower than simple carbohydrates. Glycogen is the human body’s way of storing glucose (a.k.a blood sugar) for later use. Glycogen is converted to glucose when the body is running low on blood sugar and glucose is converted into glycogen when blood sugar levels are high. Starch is very similar to glycogen, except it is a plant’s way of storing glucose. Fiber is a polysaccharide that cannot be broken down by the human body. Although we cannot absorb it that doesn’t mean it is useless, fiber has numerous benefits for the body.

Fiber:

• decreases the risk of heart disease
• regulates blood glucose
• promotes healthy gastrointestinal function
• encourages a healthy body weight

There are plenty of myths circulating about carbohydrates, most saying that they should be avoided for anyone trying to lose or maintain a healthy weight. However, this is not the case. Carbohydrates should account for anywhere between 45 and 65% of macronutrients consumed in the diet. This means that carbohydrates are not to be avoided! Authors Ellie Whitney and Sharon Rolfes state that “epidemiological studies find an inverse relationship between carbohydrate intake and body weight. Those with the highest carbohydrate intake have the lowest body weight and vice versa.” Now, keep in mind that they are referring to the wholesome kind of carbs, whole-grain and unrefined. On the flip side, too much sugar (i.e. monosaccharides) added into the food is associated with the presence of more body fat. “Sugar” in this case is referring to refined carbs. Also, foods high in refined sugars are lacking in protein, vitamins, minerals, and fiber which whole-grain carbohydrates have. Thankfully, we can easily omit these unfulfilling types of carbohydrates from our diets. For example, a sweet ice tea can be replaced with a glass of unsweetened tea or water.  Another example is replacing a sugary cereal like Cinnamon Toast Crunch with Cheerios.

In conclusion, there are two key points to take away from this post. The first is that carbs are not always your enemy. The occasional additional sugar can sweeten your day without ruining your diet. The second is that carbs are not always beneficial for you. Too much added sugar will do more harm than good.

--Hannah

Clark, N. (2014). Carbohydrate: Simplifying a Complex Topic. In Nancy Clarks' Sports Nutrition Guidebook (5th ed., pp. 111 - 135). Newton, MA: Sports Nutrition Services.

References

Sizer, F., & Whitney, E. (2012). Carbohydrates: Sugar, Starch, Glycogen, and Fiber. In Nutrition: Concepts and Controversies (12th ed., pp. 109, 111, GL-4). Belmont, California: Yolanda Cossio.

Whitney, E., & Rolfes, S. (2013). The Carbohydrates: Sugars, Starches, and Fibers. In Understanding Nutrition (13th ed., p. 99, 118,125). Belmont, California: Yolanda Cossio.

Taubes, G. (2008). Diabetes and the Carbohydrate Hypothesis. In Good calories, bad calories: Fats, carbs, and the controversial science of diet and health (p. 112). New York, New York: Anchor Books.

Clark, N. (2014). Carbohydrate: Simplifying a Complex Topic. In Nancy Clarks' Sports Nutrition Guidebook (5th ed., pp. 111 - 135). Newton, MA: Sports Nutrition Services.

Welcome Readers!!

Too many times we find ourselves clueless when it comes to healthy food choices (as a college student, I know all too well that convenience can easily trump quality selections.) I regularly hear the phrase “eat healthy” without being taught what that actually means or how to do so. Unfortunately, the frustrations of a wholesome diet cause many  people to give up on a healthy lifestyle. How do we know what is better for our bodies? When we live an active life what foods help our muscle perform better? Therefore, the goal of this blog is to break down diet and nutrition into bite sized pieces.

Together we, Sara and Hannah, have created this blog to try to answer these questions and further our independent learning. We are both in the Athletic Training Program at Grand Valley State University. Although, the education course includes a lot of anatomy, physiology, and other classes involving the physical science, nutrition is left out. We are both very excited to learn more and share the facts, bust myths and find new insights that revolve around a healthy diet. We want to encompass it all, especially focusing what we will use in our future careers. We hope our posts are directed to anyone with a similar passion of learning or interest in nutrition.