Posts Tagged ‘nutrition’

Homemade soft pretzel (plain) - Photo credit Bryan Ochalla - Used unmodified via Flickr, under CC BY-SA 2.0 license

Photo Credit: Bryan Ochalla via Flickr
Used unmodified under CC BY-SA 2.0 license

By Shelly Najjar

Carbohydrates (carbs) are mentioned a lot, by many people. In November you hear about carbohydrates because of Thanksgiving feasts and American Diabetes Month. In January you hear about people going on low-carb diets for weight loss. In the summer people try to give up carbohydrates for swimsuit bodies. Carbohydrates are in the news and in conversation, but what are they? Do we need them? Are they bad? Do they make you gain weight? This post is an introduction to carbohydrates.

What is a carbohydrate?

Medical Dictionary Definition:

any of various neutral compounds of carbon, hydrogen, and oxygen (as sugars, starches, and celluloses) most of which are formed by green plants and which constitute a major class of animal foods –Merriam-Webster Medical Dictionary

Real Life Definition:

Carbohydrates are compounds that occur naturally in foods (and can also be manufactured and added to foods) in three types (starches, sugars, and fibers).

What foods have carbohydrates?

Carbohydrates are found in dairy, starches, fruit, sweetened beverages, and dessert sweets. There can be added or naturally occurring carbohydrates in any of these. Foods do not have to taste sweet to have carbohydrates. Some examples include

  • Dairy: milk, chocolate milk, ice cream, frozen yogurt, and regular or flavored yogurt (not cheese)
  • Starches: any type of pasta, bread, rice, beans, starchy vegetables (potatoes, corn, peas, lentils, etc), crackers, cereal, etc (any starchy food)
  • Fruit: apples, oranges, grapes, melon, berries, fruit juice, etc (any fruit)
  • Beverages: fruit juice, lattes, chocolate milk, sweet tea, non-diet sodas, energy drinks, etc (any drink sweetened with anything other than non-caloric sweetener)
  • Sweets: cake, cookies, pies, candy, etc (anything made with starch or fruit ingredients and/or sweetened with anything other than non-caloric sweetener)

Plain meats, fish, poultry, cheese, eggs, and tofu (all without added sauces, which could contain carbohydrates) do not have carbohydrates. Also, non-starchy vegetables like broccoli, avocado, lettuce, carrots, onion, etc. are not counted to have carbohydrates if eaten in portions less than 1/2 cup cooked or 1 cup raw.

Are some carbohydrates better than others?

Some carbohydrates affect our blood sugar more than others, and have different benefits. The three main types of carbohydrates are starch, sugar, and fiber.

Once digested and absorbed in the body, starch and sugar raise our blood sugar, while fiber, the indigestible carbohydrate, does not have the same effect on our blood sugar. Fiber is not digested or absorbed by our bodies, but it does make us feel full and have many health benefits, so fiber-containing foods are recommended as a part of a healthy diet. Whole grain foods (which has all parts of the grain: endosperm, germ, and bran) have fiber and starch, are also recommended for overall health.

Most starches are digestible in our small intestines and will affect blood sugar, but there is also a type of starch called resistant starch that behaves more like fiber, since it continues into the large intestine without being digested. And, like fiber, many resistant starches can be digested or fermented by the bacteria in our large intestine, which helps us stay healthy (Source: Weisenberger, 2012).

Sugars can be naturally occurring or added to foods. Examples of foods with naturally occurring sugars are apples and milk. Added sugar is in many candies, cookies, and canned fruits in syrup, and includes sugars like honey, agave syrup, maple syrup, raw sugar, etc. Even if the food (like honey) has sugar naturally, when used as a sweetener, it counts as an added sugar. In general, the recommendation is to eat as few added sugars as possible.

Are carbs bad for us? Do they make you gain weight? How many carbs do we need?

Carbohydrates are neutral. We need carbohydrates to live, but too many or too few of them in our diets can cause problems. Carbohydrates on their own do not cause a person to gain or lose weight. Weight changes are caused by a variety of factors, including diet. According to the 2010 Dietary Guidelines for Americans (DGA2010):

“Strong evidence shows that there is no optimal proportion of macronutrients [macronutrients include carbs, fat, and protein] that can facilitate weight loss or can assist in maintaining weight loss […] evidence shows that the critical issue is not the relative proportion of macronutrients in the diet, but whether or not the eating pattern is reduced in calories and the individual is able to maintain a reduced-calorie intake over time. The total number of calories consumed is the essential dietary factor relevant to body weight.”

It goes on to say that we can choose healthy eating patterns that work for us, as long as they are within the right caloric range for us, and are consistent with the Acceptable Macronutrient Distribution Ranges (AMDR) established by the Institute of Medicine. The AMDRs are “ranges for the percentage of calories in the diet that should come from carbohydrate, protein, and fat” and “take into account both chronic disease risk reduction and intake of essential nutrients” (Source: DGA2010). Based on the ADMRs, we should eat between 45-65% of our total calories from carbohydrates. This includes all sources and types of carbohydrates and should be based on how your body responds and your overall health. (Your medical team can help you decide exactly how many carbohydrates you should eat – Click here to find a dietitian).

In general, most healthy people do well with about 45-50% (about half) of their calories coming from carbohydrates. For someone eating 1800 calories, this is about 200-225 grams of carbohydrates, spread out evenly throughout the day (usually about 45-60 grams at each of 3 meals, plus about 15 grams at 2 snacks between meals). Carbohydrates should come from a variety of foods, including many fiber-containing foods. Here are some helpful guides to let you know how many grams of carbohydrates are in how much of certain foods:

Summary:

  • Carbohydrates come in many types, from many foods.
  • We need carbohydrates to live, and they can and should be part of a healthy diet, coming from a variety of healthy foods.
  • While most people seem do well on a diet with up to half their calories coming from carbohydrates (about 45-60 grams carbohydrate per meal), only a medical team can help you decide what your specific health situation requires.

Read More:


Shelly Najjar, MPH, RDN is a Registered Dietitian Nutritionist and editor of Nutrition Nuts and Bolts. You can contact her on Twitter (@ShellyNajjar), LinkedIn, and at shellynajjar.com.

Like this post? You can support me and this blog if you click here before shopping on Amazon, so that a small commission on whatever you buy will be sent to me at no extra cost to you.

Advertisements

Guest post by Carrie Dennett

Deep fried pastry sticks. Photo Credit: vanillaechoes (via FreeDigitalPhotos.net)

Photo Credit: vanillaechoes (via FreeDigitalPhotos.net)
Fried foods, like these deep fried pastries, can be a source of trans fat.

A revolution is under way in the food industry, spurred by science, consumer demand and legal pressure. Trans fats, otherwise known as hydrogenated and partially hydrogenated oils, are surely and steadily being removed from our food. It’s a good thing.

Once hailed as a healthier alternative to saturated fats, trans fats are now being called “metabolic poison” by some health and nutrition experts. Unfortunately, these artificially derived fats made their way into all areas of our food supply, and stayed there for decades, before their true nature was revealed.

What is a “fat”? What is a “fatty acid”?

A fat, also known as a triglyceride, is composed of three fatty acids attached to a glycerol “backbone.” A triglyceride can have three matching fatty acids, or contain a mix (see image below). A fatty acid is made up of a chain of carbon atoms with hydrogen atoms attached. Each type of fatty acid is defined by the length of its carbon chain and how “saturated” it is with hydrogen atoms.

Why is some fat solid at room temperature while others are liquid?

A saturated fatty acid is filled up with hydrogen atoms, which makes the carbon chain straight. An unsaturated fatty acid is missing one (monounsaturated) or more (polyunsaturated) hydrogen atoms, causing the carbon chain to bend at each missing hydrogen.

A triglyceride with saturated fatty acids is compact because the straight fatty acid “tails” fit neatly together, and the resulting fat is solid at room temperature (i.e., butter or the fatty streaks in bacon). If the triglyceride contains unsaturated fatty acids, the bends in the carbon chains create space between the fatty acid tails, and that space makes the resulting fat fluid at room temperature (i.e., oils) (see image below).

Saturated and monounsaturated cis and trans triglycerides. Image created using eMolecules.com

–Triglycerides have 3 fatty acids attached to a glycerol backbone. –The fatty acids can all be the same (A) or can be different (B and C). –Saturated fatty acids “stack” nicely with each other and with other saturated triglycerides (A). –Unsaturated fatty acids can be trans or cis. The cis form has bends in it that affect how the fatty acids “stack” together (B), but the trans form (C) “stacks” like the saturated fatty acids. Image created using eMolecules.com

A trans fat is an unsaturated fat (usually polyunsaturated) that has been hydrogenated. The hydrogenation process forces extra hydrogen atoms  into the empty slots on the carbon chain, creating an unsaturated fatty acid that looks like a saturated fatty acid. Because saturated fats were linked to heart disease and unsaturated fats were known to be heart-healthy, it was believed that trans fats, would offer the best of both worlds: Heart-healthy unsaturated fats with the culinary properties of saturated fats. As anyone who likes to bake knows, there are some recipes that require a solid fat like butter or shortening.

As it turns out, once unsaturated fats are hydrogenated, they are no longer heart-healthy. In fact, they are even worse for heart health than saturated fats. One reason may be that hydrogenated trans fats are artificial—they don’t occur in nature (very small amounts of natural trans fats are present in meat and dairy products).

Why did it take so long to do something about trans fats?

Although some experts expressed concern about trans fats in their early days, it took decades before their voices (together with mounting scientific evidence) grew loud enough that the mistake could no longer be ignored. In the meantime, trans fats had seeped into all areas of food preparation. Restaurants were frying in hydrogenated oils (trans fats) instead of beef tallow (saturated fat). Home cooks got the message that margarine (trans fats) was heart-healthy and that butter (saturated fat) was not. You would be hard pressed to pick up a box of crackers or cupcakes without seeing hydrogenated oil in the ingredient list.

Finally, we’ve arrived at the point where restaurants and food manufacturers are turning away from trans fats. Trouble is, when you remove a major ingredient, you need to replace it with something.

What exactly is taking the place of trans fats?

Trans fats, and saturated fats before them, were valued for their stability at high heat. Any replacements for trans fats need to have similar qualities.

For commercial frying, partially hydrogenated oils are being replaced by vegetable oils that are naturally stable at high heat (corn, cottonseed, palm, peanut and rice bran) as well as sunflower, soybean and canola oils that have been modified to make them less likely to break down and become rancid at high heat.

The situation becomes trickier when looking for a replacement for solid hydrogenated fats, such as those used for baking. Any candidate must have the right texture and creaming ability, and it can’t turn to liquid too soon. It’s also important that the fat doesn’t go rancid quickly, so the product will be shelf-stable. The trend so far is to produce trans fat-free shortenings using either palm oil or interesterified vegetable oil.

What is palm oil? What are the pros and cons?

Palm oil is a tropical oil that comes from the fruit portion of the palm fruit (as opposed to palm kernel oil, which comes from the kernel of the palm fruit). Palm oil is rich in palmitic acid, a saturated fat, but there is disagreement among scientists and health experts about the effect palmitic acid may have on blood cholesterol and heart disease. Additionally, there are environmental concerns about the harvesting of palm oil.

What is interesterified oil? What are the pros and cons?

Interesterified oils have been used since the 1930s, but interest in them increased as trans fats began to be taken out of foods. Interesterified oils take a small amount of unsaturated triglycerides (usually soybean or cottonseed), fully hydrogenate them, then mix them with a lot of the non-hydrogenated oil. The triglycerides in the mixture are broken apart and their fatty acids rearranged, producing oil that is solid at room temperature. If you buy trans fat-free shortening or chocolate bars that have had their cocoa butter removed, you’re using interesterified oil.

The concern is that whether interesterified oil is harmful to our health or simply neutral may depend on exactly how the fatty acids in the triglyceride get rearranged. Scientists are finding that it’s not just the type of fatty acid that matters, it’s also the position it occupies on the triglyceride. The interesterification process is not precisely controlled, and some of the random arrangements produce triglycerides that are not found in nature.

What are health experts saying about these trans fat “alternatives”?

Most health and nutrition experts agree that palm oil is a lesser evil than trans fats, even if they don’t agree on whether palm oil is good, bad or neutral for health. Many experts also agree that research needs to continue on the possible effects of interesterified oil on health, especially if our consumption of it goes up due to increased use in commercial food preparation.

What can I do now until we know more about these fats?

  • First, don’t assume that the words “trans fat free” on a food package means that food is healthy. It’s wise to also consider what else is in the food. Is it high in…
    • Sugar?
    • Refined flour?
    • Artificial ingredients?
  • Second, if you eat more whole foods and fewer processed foods, you’ll naturally be eating less of whatever type of fat is used in place of trans fats. This means you will be less affected if years from now it turns out that these trans fat alternatives aren’t any better for us.

If you’d like to read more, Harvard School of Public Health’s Nutrition Source website has a nice page on trans fats.

Carrie Dennett is a MPH student in the Nutritional Sciences Department and the Graduate Coordinated Program in Dietetics at the University of Washington. She writes a nutrition column for The Seattle Times; “On Nutrition” runs on the health page every third Sunday. She also blogs at Nutrition by Carrie.


Also read…

Any video appearing below this line is advertising and not part of this post
__________________________________________________________

By Shelly Najjar

Bunch of yellow bananas by adamr via FreeDigitalPhotos.net

Photo Credit: adamr (via FreeDigitalPhotos.net)

Can you list at least 3 foods that have more than 500 mg of potassium? (Hint: one is in the title of this post.) If you can’t, that’s okay. A few days ago, I couldn’t either.

A family friend asked me to find some information about potassium, including how much she should get every day and what foods she should be eating to reach that goal. I couldn’t tell her off the top of my head (even though we’ve had assignments on this topic in the past) so I told her I’d get some resources for her.

What is potassium? What does it do?

Potassium is an element/mineral that helps maintain electrolyte and pH balance, affects muscle contraction (including the heart muscle), and allows nerves to transfer signals more efficiently.

How does it work?

Many cells in our body use potassium to transfer other ions (electrically charged particles) across membranes. Sodium (another electrolyte and a part of table salt) has a negative charge. Potassium has a positive charge. These signals are important because they affect how well a signal can travel through the cell (like what nerve cells do).

Potassium and sodium are also transferred in and out of the cells to maintain fluid balance, because water likes to collect in areas where there is a lot of sodium. If the inside of a cell has too much sodium, water will be drawn in to dilute it, through the process of osmosis (water moving from an area of low concentration to an area of high concentration). If too much water collects in the cell, it will burst.

One of the things cells do to prevent this from happening is to exchange sodium for potassium (potassium molecules are pulled into the cell and sodium molecules are pushed out).

Where is it found?

Obviously, potassium is important. It is in many foods, including

  • baked potatoes with skin (925 mg/medium potato)
  • canned white beans (595 mg/cup), and
  • canned clams (535 mg/3 oz).

(Note: You should now be able to answer the potassium question at the beginning of this post.)

There are a couple of lists of potassium-containing foods that I want to share with you.

  1. The first is a list sorted by the amount of potassium per serving: Food Sources of Potassium.
  2. The second is a more comprehensive list, organized by food groups separated into three categories (High Potassium, Moderate Potassium, and Lower Potassium foods), and then alphabetized by food name, rather than by amount: Potassium Values of Food.

How much do we need?

The recommendation for adults without kidney disease ages 19 and over is 4,700 mg (milligrams) of potassium daily. (See the Dietary Reference Intakes. They list it in grams, so you may need to know that 1 g = 1,000 mg.) Dietary Reference Intakes are listed by age and sex for each nutrient.

Important: Your health care professional may recommend a different daily amount if you have certain medical conditions, including but not limited to kidney disease or hypertension (high blood pressure). Please consult a doctor or Registered Dietitian. Also, see my disclosure.

Summary

  • Potassium is a mineral that our bodies need to work properly.
  • Many foods contain potassium. Besides potatoes and bananas, some foods with high potassium (more than 200 mg per serving) are avocados, fish, chocolate milk, and turkey. The two lists mentioned above contain many more options.
  • The recommendation for most adults is 4,700 mg of potassium daily.

Also read…

Shelly Najjar, MPH, RDN is a Registered Dietitian Nutritionist and editor of Nutrition Nuts and Bolts. You can find her on Twitter (@ShellyNajjar), LinkedIn, and at shellynajjar.com.

Like this post? You can support me and this blog if you click here before shopping on Amazon, so that a small commission on whatever you buy will be sent to me at no extra cost to you.

by Shelly Najjar

Apart from being a word that connects two thoughts, what is the AND?

Who and What

The Academy of Nutrition and Dietetics (AND) is the new name for what used to be called the American Dietetic Association (ADA). It is “the world’s largest organization of food and nutrition professionals” and has more than 75,000 members (source). 72% of those members are Registered Dietitians (read the post I wrote about that topic).

Where

AND headquarters is located in Chicago, Illinois. They also have an office in Washington, DC.

Why

The website, eatright.org, lists its Mission and Vision:

Mission — Empowering members to be the nation’s food and nutrition leaders

Vision — Optimizing the nation’s health through food and nutrition

How

The AND website lists 6 ways in which it “strives to improve the nation’s health and advance the profession of dietetics through research, education, and advocacy.”

  • Providing Reliable and Evidence-based Nutrition Information for the Public
  • Accrediting Undergraduate and Graduate Programs
  • Credentialing Dietetics Professionals
  • Advocating for Public Policy
  • Publishing a Peer-reviewed Periodical: Journal of the Academy of Nutrition and Dietetics
  • Giving Back: the Academy of Nutrition and Dietetics Foundation

You can read more about these efforts at the AND’s website.

Shelly Najjar, MPH, RDN is a Registered Dietitian Nutritionist and editor of Nutrition Nuts and Bolts. You can find her on Twitter (@ShellyNajjar), LinkedIn, and at shellynajjar.com.

Like this post? You can support me and this blog if you click here before shopping on Amazon, so that a small commission on whatever you buy will be sent to me at no extra cost to you.