Thursday, October 3, 2013

Exercise: The Best Medicine

A very interesting article was just published in the British Medical Journal. The researchers reviewed meta-analysis studies that compared exercise and medications to each other or placebo and the effects they had on the risk of death. Collectively, these studies suggest that exercise and medications have similar outcomes when it comes to lowering death. 

A quick lesson about Meta-Analyses:  Any time you see an article that talks about results of a meta-analysis, you should proceed with caution!  A meta-analysis is tricky business. Researchers combine data from several studies and reanalyze it as one study. They do this when there are few large, definitive studies in a specific research area. So they take a bunch of studies that meet their specific criteria as far as study design, research variables, study participant characteristics, etc. and crunch the data together. This method is imperfect at best because no matter how similar studies may be, the differences in how the data were gathered can result in much less precise results when you put all the data together. That said, these studies can be useful in areas where larger studies are lacking.  And if the researchers conducting the meta-analyses use rigorous methods, then the data can at least be somewhat useful. 

What this study found: The results of this particular meta-analyses are particular interesting and encouraging. The researchers looked at studies that looked at deaths related to heart disease, stroke, heart failure, and pre-diabetes. The risk of all of these diseases can be lowered by diet and exercise. But no one has ever shown if exercise by itself can reduce the risk of dying from these diseases or if exercise is as effective as medicines in lowering the risk of dying from these diseases. 
For heart disease and prediabetes, the researchers found that exercise was just as effective as medicines for preventing deaths caused by these two common diseases. In the case of stroke, exercise was found to be more effective than medicines in preventing death from stroke. 

What kind of exercise? Because the studies reviewed were meta-analyses, the exercise programs in each of the studies were different. Most used a combination of muscle strengthening exercises and aerobic exercise like walking, biking, or swimming.
The exciting message – that we do have to approach with caution – exercise may be as effective – and in some cases more effective – than medicines when it comes to treating several  of the diseases that Americans are most likely to die from. Since medicines can be expensive and have possible side effects, this is a good news message. And don’t forget that exercise has other benefits as well such as improving mood and your ability to do the day to day activities you need and want to do.

Beth Kitchin, PhD, RDN
Assistant Professor,Nutrition Sciences
University of Alabama at Birmingham

Naci, H. & Ioannidis, J. Comparative effectiveness of exercise and drug interventions on mortality outcomes: metaepidemiological study. 2013. BMJ 347:f5577.

Monday, September 9, 2013

Extra Protein May Minimize Muscle Loss During Dieting

The Study  One of the big challenges of losing weight is preventing muscle loss. When you lose weight by cutting calories, you always lose some of that as fat and some of that as muscle. But you want to minimize that muscle loss because muscle burns more calories than fat and also helps to keep you strong.
In a recently published study, researchers showed that when study participants on a weight loss diet were put on twice the recommended level of protein, they lost more fat and less muscle than the participants at the recommended level of protein intake. Participants who ate three times the amount of recommended protein did not get any extra benefit.
Everyone lost weight in the study – about 7 pounds for the people on the lower protein diet and just under 6 pounds for the people on the double protein diet over 21 days. But the people on the lower amount of protein (the recommended level) lost 58% of their weight as muscle while the people in the 2x protein group only lost 30% of their weight as muscle. The other 70% of weight lost was as fat.

Some cautions on this research:
  • Small Study.  There were 12 to 14 people in each of the study groups – that’s small and those 12 to 14 people may not be like the rest of us! 
  • Short Study. The weight loss portion of the study only lasted 21 days – so we can’t say what would happen long term.  
  • Was it the protein? It is possible that because the people in the double protein group lost a little less weight, that the lower weight loss itself could have accounted for losing less weight as muscle.
So this finding is not conclusive by any means but it does raise this idea that we may be able to minimize muscle loss on a low calorie diet by boosting protein.

Protein Recommendations
  So what is the recommended level of protein now? It is 0.8 grams of protein per kilogram of body weight. To change your body weight from pounds to kilograms, you divide by 2.2. So the protein needs for someone who weighs 220 pounds looks like this:

220/2.2 = 100 kilograms body weight    
100 kilograms x 0.8 grams/kilogram of protein = 80 grams of protein

So, if this person wanted to lose weight, you would double that to 160 grams of protein a day. Now things get a little complicated at this point because the rest of the diet also has to be adjusted to accommodate this increase in protein. Just increasing your protein intake won’t help you lose weight. In fact, you would probably gain weight from the extra calories!

So, you have to lower your overall calorie intake to a reasonable level that will help you lose weight. Then, you have to calculate how much fat and carbohydrates fit into your diet. In this study, the researchers had the participants eat less than 30% of their calories as fat and then added the rest of the calories in as carbohydrate. The bottom line is that you may want to consult with a registered dietitian to help you devise a plan that is accurate and works for you! Getting all that extra protein may not be as easy as you think. Here’s a list of the top dietary sources:

Best Protein Sources:
4 ounces of lean meat: 28 grams
1 cup skim milk: 8 grams
1 egg: 6 grams
4 ounces Greek yogurt: 12-14 grams
1 ounce of cheese: 7 grams
½ cup tofu: 10 grams
1 cup soy milk: 6 grams
½ cup pinto beans: 7 grams

Beth Kitchin PhD, RD
Assistant Professor Nutrition Sciences
University of Alabama at Birmingham

Source: Pasiakos, S. M., Cao, J. J.,Margolis, L. M., Sauter, E. R., Whigham, L. D., Mc-
Clung, J. P., Rood, J. C., Carbone, J. W., Combs, G. F.,Jr., Young, A. J.
Effects of high-protein diets on fat-free mass and muscle protein synthesis following weight loss: a randomized controlled trial. FASEB J. 27,
3837–3847 (2013).

Monday, July 1, 2013

Short on Sleep May Mean More Calories – and Weight Gain

     Over the past several years, the evidence that points to lack of sleep as a contributing factor to overeating has increased. In a 2010 study, researchers put 10 overweight participants on a moderately low calorie diet and then let them sleep up to either 8.5 hours or 5.5 hours for two weeks. They then switched participants to the other sleep group for another two weeks. They measured weight and body composition (fat vs. muscle) after each two period.  
Here’s what they found:
  • More Sleep, More Fat Loss. When people got more sleep, they lost more of their weight as fat (3 pounds vs. 1.3 pounds) and less of their weight as muscle (3 pounds vs. 5 pounds).
  • Less Sleep, Higher Hunger. When people got less sleep, they were hungrier. Their levels of a hormone called ghrelin were higher than when they were allowed to sleep longer. Ghrelin is a hormone in the stomach that makes you hungry.

      A study published last year in the Annals of Internal Medicine gives us a clue as to how a lack of sleep contributes to insulin resistance – which can lead to obesity and heart disease. The researchers found that when people were sleep deprived, their fat cells ability to respond to insulin dropped by about 30%. 
      But both of these studies were very small and inconclusive. Now a study published in this month’s edition of the journal Sleep, adds to the data. And this was a big study – 225 people. In this study, the researchers found that the people who were allowed only four hours of sleep over 5 consecutive days ate 500 calories above their needs a day and gained about 2 pound over the following 9 days. The people who were not sleep deprived did not eat extra calories above their needs nor did they gain any weight.  This was a short-term study so we cannot say whether these changes would remain over the long haul.
      Now, getting more sleep alone is not going to make you fit into your bikini in time for summer vacation. For one thing, not everyone is sleep deprived and not everyone who is sleep deprived overeats as a result. But lack of sleep could be contributing to America’s weight problem. The Centers for Disease Control reports that over 20% of Americans are getting 6 or fewer hours of sleep a night – well below the seven to nine we need.
So here are some tips to get the best sleep:
  • Stay Calm Before Sleep: avoid caffeine, alcohol, troubling reading, and over stimulating, violent TV at bedtime
  • Avoid Energizing Activities Before Bed: avoid exercise and bright lights around bedtime; try dim lights, meditative thoughts, and warm milk (yuck!).  A warm bath right before bed can help with sleep. Computers and cell phones seem to stimulate brain activity so avoid them before bed!
  • Set the Stage: make sure your bedroom has curtains that are heavy and keep your room dark.
  • Make Sleep a Priority:  just like you make time for your family, exercise, and eating, making the time to sleep should be just as important.

Now if only we could find a way to add more hours to the day!

Beth Kitchin PhD RDN
Assistant Professor, Department of Nutrition Sciences
University of Alabama at Birmingham

Nedeltcheva AV et al. Insufficient sleep undermines dietary efforts to reduce adiposity. Ann Intern Med. 2010;153:435-441.

Broussard JL, Ehrmann DA, Van Cauter E, Tasali E & Brady MJ. Impaired insulin signaling in human adipocytes after experimental  sleep restriction: a randomized, crossover study. 2012; 549-557.

Spaeth AM, Dinges DF & Goel N. Effects of experimental sleep restriction on weight gain, caloric intake, and meal timing in healthy adults. Sleep. 2013

Friday, March 22, 2013

The Myth of Sugar-Loving Tumors

I went out to dinner with a friend of mine last night who asked me if sugar feeds tumors. He had seen some sort of presentation where someone showed sugar being taken up by tumors.   I see these kinds of things on Facebook posts all the time and scroll by.  But when friends pose these questions to me over a plate of pasta, I take the concern a little more seriously.  
                So what are the facts here? Well, cancer cells and tumors need calories and nutrients just like the healthy cells in our bodies.  While cancer cells do feed off sugar, healthy cells do too. So yes, if you give a tumor sugar in a petri dish it will surely be taken up by the cancer cells – but so will all the other cells of your body.  It also makes for some nice scary pictures to post on Facebook and for an overly simplistic message about how cancer cells operate.
                Research shows that eating sugar doesn’t speed up cancer growth.  If you want to shut off what feeds cancer, you have to shut off what feeds all of your cells. You would starve and kill the cancer cells but you would also starve and kill healthy cells and die.  Some research shows that there may be some sort of link between high insulin levels and growth of some cancers.  Some people pump out too much insulin when they eat too many carbohydrates.  But many of us have normal insulin levels. 
                We do know that obesity may be a risk factor some cancers. So eating too much sugar and other calorie dense foods could be an indirect factor in some cancers. In fact, one of the first recommendations by the American Institute for Cancer Research for cancer prevention is to be as thin as possible without being underweight.  They also recommend eating fewer calorie dense foods – including sugar sweetened beverages. These foods can increase weight.  It’s the weight gain that can lead to many problems – including too much insulin – and that increases the risk of some cancers.
                But notice I said some cancers.  And this is another area of misconception about cancer. Cancer is not just one disease. While there are common themes to all cancers – such as all cancers start with some sort damage to genes –  risk factors and causes of each of the cancers are not always the same. For instance, the human papilloma virus is a cause of cervical cancer and possibly some oral cancers but not of other types of cancers.  Weight gain seems to be a risk factor for cancers in the esophagus, pancreas, colon/rectum, endometrium, kidney, gallbladder, and postmenopausal breast cancers. It may not be much of a risk factor for cancers in the lung, ovaries, or stomach.
                The bottom line is that we should all be moderate with sugar. But it is the not the tumor-feeding fiend a lot of people make it out to be.  You can also check out this excellent explanation of this myth on the Mayo Clinic website.
Beth Kitchin PhD RD
Assistant Professor, Nutrition Sciences
University of Alabama at Birmingham 

Monday, March 18, 2013

Hydration Nation: The 8 Cups of Water a Day Myth

Most people have heard that they need to drink 8 cups of water every day to be healthy. And water is crucial to helping our bodies work right – so it’s not surprising that water is responsible for 60% of our body weight.  But do you really need to guzzle at least 8 cups a day? Our bodies lose water every day through the kidneys in the urine, from the lungs when we breathe, and through sweating. The typical person does lose about 8 to 12 cups of water a day through these routes but, as it turns out, there are many ways you can replace that loss.
Restoring Water:
Ø  Milk & Juice: When you drink milk or juice not only are you getting vitamins, minerals, and in the case of milk, protein, you’re also replacing water loss. Both milk and juice are over 80% water so they can really make a dent in body water needs.
Ø  Coffee & Tea. These two always surprise people because many people are led to believe that the caffeine in caffeinated beverages makes them lose all the water in the beverage & then some causing an overall water deficit. Not so! Yes, it is true that caffeinated beverages are not as good as non-caf in helping you hydrate but you still get some hydration effect. In other words, you urinate a little more with caffeinated beverages but remember, you're getting a lot of water in that coffee, tea, or soda and you retain over 50% of it. Researchers have also shown that most people adjust to the caffeine level in their drinks so over time, so the caffeine does not have as much of an effect on your body. After about 3 to 5 days of drinking caffeinated beverages, the body adjusts and there is no additional loss of urine when compared to decaffeinated beverages.  
Ø  Soda.  Even soda can help you rehydrate – it’s mostly water. Your best bet is diet sodas so that you’re not adding in empty calories.
Ø  Fruits & vegetables. Fruit & vegetables contain a lot of water. Strawberries, watermelon, lettuce, cabbage, celery, spinach, & broccoli are particularly high at over 90% water. The water content of most other fruits & vegetables is over 80% so they are also good sources. For many people, fruits & vegetables can contribute 1/3 or more of their daily water needs!
Ø  Other foods. All foods contain some water, but notable water contributors include yogurt, cottage & ricotta cheeses, fish, chicken, and pasta.
Ø  Water: Water is the best hydrator – it empties from the stomach quickly and makes its way to the large intestine where it can be absorbed quicker than the other fluids.
Ø  Thirsty? Thirst is actually a pretty good guide to whether or not you need more fluids – except in older people.
Ø  Check Your Urine. The best way to tell if you are getting enough fluids is to check your urine. If you are well-hydrated, your urine will be very pale. If you need fluids, the urine is dark yellow and low in amount.
While drinking water is still a good idea, you don’t have to feel like you’re drowning in it or lug a massive, back-breaking water jug around all day long.  All beverages (except alcohol) count toward your total 8 to 12 cups and eating a lot of fruits and vegetables will also help keep you hydrated.
Can you get too much water? Surprisingly, yes! People who chug water excessively can actually dilute out their blood sodium levels to a dangerously low level. The fancy name for this is hyponatremia. Some of the symptoms can mimic dehydration – muscle weakness, muscle cramps, confusion, and decreased consciousness. It can result in death!
Beth Kitchin PhD RDN
Assistant Professor, Nutrition Sciences
University of Alabama at Birmingham