If you’re trying to eat right, you almost never go wrong with eating more fruits and vegetables.
But what’s the deal with potatoes? They’re a starchy vegetable, with more calories and a higher glycemic index than most of their vegetable counterparts. Potatoes often get a bad rap, but don’t spurn your spuds just yet…
Potatoes on Parade
First, some context. Potatoes are in the spotlight this week due to a study published in the British Medical Journal that found potato eaters have higher rates of hypertension (high blood pressure).
The study looked at over 187,000 subjects from 3 US cohort studies and found that, “higher intake of baked, boiled, or mashed potatoes and French fries was independently and prospectively associated with an increased risk of developing hypertension…”
So are potatoes to be passed off as a hypertension causing tuber? Not so fast.
According to the USDA Economic Research Service, more than 50 percent of potatoes sold in the US are to processors who turn them into things like hash browns, processed mashed potatoes and French fries. We’re not talking healthy serving sizes of roasted pure potato here. These are convenience foods with significant amounts of added fat…and salt.
And that’s where the hypertension piece comes in – the most processed food you eat, the more sodium you consume, and the higher your risk of blood pressure can be.
Potassium and Blood Pressure
Potatoes on their own actually have the potential to LOWER blood pressure. That’s because they contain potassium, an essential mineral that works to reduce elevated blood pressure. Potassium is found in most fruits and vegetables (albeit in higher quantities in potatoes, bananas, and tomatoes). And it’s these same foods – fruits and vegetables – that are also naturally low in sodium. The combination of low sodium and high potassium intake from fruit and vegetables can work to help lower your blood pressure.
The kicker is what you do with foods like potatoes that really matter. If you are more likely to eat your potatoes as French fries, of course your risk of high blood pressure will go up. Even baked and boiled potatoes were associated with higher BP risk….but keep in mind there’s a greater than 50 percent chance those potatoes were processed with added fat and salt.
At the end of the day, the more whole, intact foods you can eat, the better for your health. Stay away from foods that come in packages and keep your added salt and fat to a minimum. And when it comes to picking potatoes, steer clear of the chips, fries and other processed versions.
Did you know that there are more bacteria in your intestine than there are cells in your body? Unbelievable, right? Moreover, it turns out that these bugs actually contribute to health and disease. This is a hot topic in the scientific world and it turns out that a lot of nutrition scientists are quite interested in this area of research. What then, you might ask, is the link between nutrition and gut bacteria (or the so-called ‘gut microbiota’), and how exactly do they influence one’s health and well-being? Great questions! Let’s explore these concepts.
In a healthy person, most nutrients are digested and absorbed in the small intestine. This includes mono-and disaccharides (i.e. simple sugars), amino acids derived from dietary proteins and fats. Complex carbohydrates, such as soluble and insoluble fibers and resistant starches, however, cannot be digested by human enzymes and enter the large intestine (or colon) intact. This also happens to be where the bulk of bacteria reside. Interestingly, the gut microbes can then digest soluble fibers and resistant starches in the colon. Some of the breakdown products of these complex carbohydrates, called short-chain fatty acids (for example, butyrate), provide fuel for the cells lining the colon (as well as providing fuel for the bacteria that digest them). These dietary constituents have been termed ‘prebiotics’ as they feed the gut microbes. The amount of fiber in your diet can actually alter the composition of the gut microbiota, by promoting the growth of certain types of bacteria.
There are literally dozens of different bacterial species in the human intestine, some are beneficial to us and others can be harmful under certain conditions. It turns out that changes in the composition of the gut microbiota can increase the risk for: functional bowel disorders, inflammatory bowel diseases, celiac disease, food allergies, type 2 diabetes, obesity, autism and even depression (Science Daily Article).
So, consumption of prebiotics is one way to positively influence the gut microbiota. Are there others? Yes, probiotics. Probiotics are living bacteria that can be found added to certain foods in the grocery store. The probiotic bacteria added to these foods populate the gut with good bacteria and, in principle at least, outcompete the bad bacteria, tipping the balance towards health. Probiotics have been suggested to improve resolution of diarrhea, prevent and treat urinary tract infections, treat irritable bowel syndrome, reduce bladder cancer recurrences, and prevent or reduce the severity of colds and flu (amongst other purported benefits).
So then, are you kind to your intestinal co-inhabitants by feeding them nutritious snacks (i.e. complex carbohydrates)? Or are you, like most Americans, not consuming enough fiber in your diet. How about probiotics? Do you consume foods with beneficial live bacteria? They are available at your local grocery store right now. If you answered no to these questions, you might want to think about this issue. It could positively influence your health in ways that we currently understand and in other ways that will undoubtedly be discovered in the future.
Diets are popular among Americans, although most fail at sustaining long term weight loss. They are however big business and some folks are becoming quite wealthy off of them. Of the most popular diets, Google recently reported that the most searched-for eating plan of 2013 was the Paleo Diet (Daily Mail Google Diet Searches 2013). This ranked ahead of the ‘Juice Cleanse Diet’, the ‘Mediterranean Diet’ and the ‘Master Cleanse Diet’. In contrast to its popularity among average Americans, however, U.S. News and World Report recently ranked the Paleo Diet tied for last on its “Best Diets Overall” list for 2014 (CNN Best Diet Rankings). This report was developed through consultation with a panel of health experts from top academic institutions around the country, including nutritionists and specialists in diabetes, heart health, human behavior and weight loss. This panel of experts rated each of 32 diets diet in seven categories, including short- and long-term weight loss, ease of compliance, and safety and nutrition. How could such a popular diet be ranked so low by scientific experts? There seems to be a clear disconnect between the American public’s view on dietary eating patterns and what is recommended by health experts.
Let’s take a closer look at the Paleolithic dietary pattern and explore why it is not recommended by nutrition experts. The premise of this plan is to “consume everyday modern foods that mimic food groups of our pre-agriculture, hunter-gatherer ancestors” (Paleo Diet). This includes lots of meat protein, low carbohydrate, high fiber from fruits and non-starchy vegetables, and moderate to higher fat intake, with a focus on mono- and polyunsaturated fats. This dietary pattern restricts cereal grains, legumes and dairy foods. The purported benefits include decreasing risk of obesity, cardiovascular disease, type 2 diabetes, cancer, autoimmune disease and osteoporosis, among other stated benefits. The Paleo Diet web site states that these diseases were typically very uncommon among our early ancestors, and suggests that mimicking their diets should provide the same benefits to modern humans.
If this is all true, then why don’t the experts agree? First, it’s important to consider that prehistoric humans had shortened life spans (probably less than 35 years). In fact, as recently as the mid-20th century, the average human life span was less than 50 years. Another factor to consider is whether we really know how these early humans died and what diseases they suffered from, or exactly what they ate. Other aspects of the Paleo Diet were however considered negatives by the expert panel that ranked the diets. Their criticisms of this dietary pattern included a lack of scientific evidence that the Paleo Diet promoted weight loss or prevented cardiovascular disease, and its restrictiveness. In fact, most nutrition experts recommend consuming more grains (particularly whole grains), legumes (as an alternative protein source to meat) and low-fat dairy products (which on a population-wide basis are amongst the best sources of calcium and vitamin D). So who will you believe, scientific experts or those selling a product on a popular web site?
Fluoridation of Public Water Supplies: Effective Health Promoting Strategy or Unwelcome Mass Medication?
Tooth decay (or dental caries) represents one of the most significant diseases worldwide, effecting over 2 billion individuals. In 2006 in the U.S., dental caries was considered the most common chronic childhood disease (Oral Health – Healthy People). A large percentage of adults in the U.S. over the age of 50 years also have dental decay. Given the large number of affected individuals and the fact that there is no way to “regrow” damaged teeth, it comes as little surprise that preventative strategies have been developed. First and foremost has been the use of fluoride, which helps prevent dental caries. It is the active ingredient in toothpaste. Moreover, fluoride is routinely added to public water supplies in many locales across the world. This sounds like a good thing, right? It actually depends upon whom you ask. The fluoridation of public water supplies has generated much controversy over the past few decades. Let’s take a closer look at the pros and cons of fluoridation of water, and see who is for and who is against it.
Water fluoridation began in the 1940s, and controversy has swirled since this time. Proponents argue, and scientific data has since proven (Systematic Review of Water Fluoridation), that fluoridation of public water supplies decreases the burden of tooth decay. Although with significant variance, scientific studies consistently show that water fluoridation decreases cavities in children (18-60% reduction). Opponents, however, argue against it for several reasons: 1) excess fluoride intake can cause serious health problems; 2) the outcomes do not justify the cost; and 3) the dosage cannot be properly controlled. In regards to point 1, there is little scientific evidence that water fluoridation causes any adverse health consequences except dental fluorosis, which is a harmless discoloration of the teeth. Point 2 is more of a philosophical stance that is clearly a matter of opinion. In reference to point 3, if properly managed, water fluoridation can be maintained at a level that promotes dental health and minimizes adverse health risks. Opponents argue that too much fluoride could cause cancer, but scientific data do not support this argument (NHMRC Public Statement: Efficacy and Safety of Fluoridation).
So, who argues for and who argues against water fluoridation? Those against it include the International Chiropractor’s Association who argue it is “possibly harmful and deprivation of the rights of citizens to be free from unwelcome mass medication”. The Sierra Club in the U.S, the Canadian Green Party and some notable scientists have also come out in opposition to water fluoridation. Those in favor include the U.S. Centers for Disease Control (CDC), the American Dental Association, Health Canada and the World Health Organization (WHO).
You now have the basic scientific facts. Who do you agree with on this issue? Will you continue to drink fluoridated water? What about bottled or filtered water, do they contain fluoride? The answer is probably no. Whatever you decide, just know that leading scientific organizations worldwide support water fluoridation and feel that these programs are among the most significant health advances of the 20th century.
In 1970, sucrose was the main food and beverage sweetener used in the U.S. Sucrose, or “table sugar”, is composed of one glucose molecule linked to a molecule of fructose. In 1970, ~15% of America were obese. Today, obesity rates are around 35% and high fructose corn syrup (HFCS) has replaced sucrose in many foods and drinks. The question that has caught the attention of many over the past several years then is: What is the association between this dramatic increase in the consumption of HFCS and the skyrocketing obesity rates in the U.S. Let’s take a closer look at this issue and see what the peer-reviewed scientific literature has to say.
Why has HFCS replaced sucrose in many foods and drinks? That’s an interesting question, but first lets’ consider the source of HFCS. It is made by extracting starch from corn, and then treating the starch to release the glucose, followed by a procedure which converts about half of the glucose to fructose. HFCS is cheaper and more stable during storage than sucrose, explaining why food manufacturers prefer to use it as a sweetener.
Studies performed in the past decade suggested that there was a direct link between increased HFCS intake and obesity. This made sense since fructose is more easily converted to fat than glucose and it may alter hormonal signals that control feeding behavior differently from glucose. Again, interesting facts, but how is the sugar content of HFCS really different from sucrose? The answer is not very different, in fact, very similar. Sucrose is 50% glucose and 50% fructose, while HFCS contains either 55% fructose/42% glucose (in sodas) or 42% fructose/ 53% glucose (used in baked goods). So as you can see, the composition of HCFS and sucrose is very similar. Why then would HFCS lead to different health consequences as compared to consumption of sucrose? The answer is that it probably does not.
A survey of the scientific literature identifies several very recent papers that conclude that from a nutritional or health-related perspective, consuming sucrose versus HFCS is not different. One recent study found that HFCS and sucrose do not differentially affect levels of “energy-regulating hormones” in humans ( Nutr. Res., 2013). Another paper in the International Journal of Obesity concluded that there was a lack of evidence to link HFCS consumption with the current obesity epidemic (Int. J. Obes., 2013). It was also noted that there was inconclusive evidence to link HFCS to childhood obesity (Ped. Obes., 2013). The consensus on this issue thus seems to be shifting.
Nutrition science tells us that greater energy in than energy out leads to weight gain over time. Not only has HFCS intake increased over the past few decades, but total energy intake has as well. Perhaps the culprit is not HFCS, but rather a change in the typical American’s lifestyle towards more food intake and less activity. Future studies will undoubtedly address this important issue further, but in the meantime, will you avoid food and beverages sweetened with HFCS? How do you think it could positively influence your health if you switched to sucrose sweetened foods and drinks? Or maybe the best approach is to decrease intake of ALL sugar sweetened foods and decrease overall energy intake in that way. What will be your approach?
You may have seen recent headlines that heralded studies indicating that diet soda consumption was related to weight gain. A USA Today headline from a July 10, 2013 article read, “Study: Diet soda doesn’t help you lose weight” (Diet Soda Article). Another on the Reader’s Digest web site asks, “Is Diet Soda Making You Fat?” (Reader’s Digest Article). Furthermore, WebMD reports that searching “diet soda” and “weight” using a popular browser found that 49 of the top 50 hits were for stories that warned readers of the link between diet soda and weight gain (WebMD Article). Why has this issue been in the news in recent months? It turns out that a few scientific studies were published over the past several months, purporting this idea that diet soda consumption may actually lead to weight gain, rather than what most people would expect, weigh loss. Let’s have a closer look at those studies and also consider this issue in light of a larger body of scientific research on this topic.
It turns that the recent attention to this issue results from studies with laboratory rats and from observational studies in humans. In the rat studies, published by Drs. Swithers and Davidson at Purdue University (Swithers S and Davidson T – PubMed – NCBI), the researchers noted an association between non-nutritive sweetner consumption (e.g. saccharin) and weight gain. The researchers suggested that rats consuming saccharin, as opposed to rats ingesting table sugar, took in more calories and gained more weigh over time. But, will this finding hold true in humans?
Other recent epidemiological studies, consisting of large numbers of people, reported that those who drank more diet sodas gained more weight over time. One study tracked more than 5000 adults in the San Antonio Heart Study. The second (the Framingham analysis) reported an association between intake of both sugar-sweetened sodas and diet sodas and development of metabolic syndrome, which is cluster of symptoms linked to obesity. However, since both of these studies were observational, it is not possible to say with certainty whether consumption of diet sodas has a direct effect on body weight.
These studies were rapidly popularized by the media and online bloggers, and soon this message was out for all to see. Interestingly, not everyone agrees with these findings and many past studies have not identified such an association. A recent review of past studies on this topic, published in the American Journal of Nutrition (AJCN Article), came to different conclusions, namely that the purported mechanisms by which non-nutritive sweetners promote energy intake and contribute to weight gain are not supported by the current available evidence. The authors do however recommend that this possibility should be further considered in long-term, randomized controlled clinical trials.
The jury is thus still out on this issue, despite all the recent negative press regarding consumption of artificial sweetners. Importantly two respected scientific organizations support the use of no calorie sweetners to restrict calorie and sugar intake (the American diabetes Association and the American Dietetic Association). This thus leaves us as individuals with a sort of dilemma. Should we restrict intake of artificial sweetners? Which studies are correct? The best advice may be to consume these food additives in moderation and await more definitive research which will undoubtedly be undertaken very soon.
Did you see the headlines today? Americans are not consuming enough fiber!… Hmmm, this really isn’t news. We’ve known for years that, as a nation, we don’t consume enough whole grains, fresh fruits, or vegetables. A recent study published in the December issue of The American Journal of Medicine (AMJ), confirms that this lack of fiber is at least partly responsible for an increased risk of metabolic syndrome, cardiovascular disease, and obesity.
How much fiber do we need?
The Institute of Medicine recommends that adults aged 19-50 years consume 25 grams of fiber per day (women) to 38 grams of fiber day (men). That may sound like a lot, but it’s surprisingly easy to meet the recommendations if you put in a little effort. It will likely require a few simple substitutions, and perhaps a couple of healthy additions.
For instance, instead of eating a highly processed breakfast cereal first thing in the morning, choose one made with whole grains (5 grams of fiber per cup). Instead of eating a sandwich for lunch made with bread from refined flour, choose bread made with whole grains (5 grams of fiber per two slices). Instead of eating refined pasta for dinner, choose whole grain pasta (5 grams of fiber per cup). And don’t forget to enjoy fruits and vegetables throughout the day as snacks –a cup of fresh fruit or vegetables is worth another 5 grams of fiber, as is half a cup of beans.
You can see that, if you focus on WHOLE GRAINS, it’s quite possible to meet the recommendations for daily fiber intake. Unfortunately, according to the recent AMJ study, Americans consume an average of just 16 grams per day! That’s roughly half of the recommendation.
Food for thought
Why do you think that most Americans do not consume enough fiber? How much fiber do you consume on a daily basis? What sorts of substitutions or additions to your diet could you make to consume more fiber?
“Dietary Fiber Intake and Cardiometabolic Risks Among US Adults, NHANES 1999-2010” by Kya N. Grooms, BA; Mark J. Ommerborn, MPH; Do Quyen Pham, MPH; Luc Djousse, MD, ScD, MPH; Cheryl R. Clark, MD, ScD. The American Journal of Medicine, Volume 126, Issue 12, December 2013.
Gluten is a protein composite found in foods processed from wheat, barley and rye (and related grains). It is found in the endosperm of the grain kernel and consists of the proteins gliadin and gluterin. Gluten gives elasticity to dough, helping it rise and keeps its shape. You may have heard or read about the health benefits of gluten-free diets and seen numerous gluten-free products in the grocery store. Proponents of gluten-free diets claim that this dietary pattern promotes weight loss and may be beneficial in numerous other ways, such as helping those with osteoporosis, anemia and diabetes. Have you wondered if this is true? Have scientific studies been conducted to back up these claims? Let’s take a closer look at some the purported health benefits and also consider who may benefit most from a gluten-free diet.
There are indeed folks that have to avoid gluten at all costs, namely, those suffering from celiac disease (also frequently called celiac sprue). This autoimmune disorder occurs in genetically predisposed people from early life onwards. People with celiac disease experience pain and discomfort in the GI tract, chronic constipation, fatigue and other symptoms. The underlying cause is related to gluten exposure. In those with celiac disease, an enzyme in the epithelium of the GI tract reacts with gluten proteins and causes an immune reaction whereby the immune system attacks the small bowel tissue. This causes an inflammatory reaction and as a result, the villi of the epithelium are blunted and malabsorption of many nutrients occurs. The only treatment for celiac disease is life-long adherence to a gluten-free diet. Clearly the preponderance of gluten-free products now available in the grocery stores benefits those with the disease. But what about other individuals, can they also benefit from gluten-free foods?
How about going gluten-free for weight loss? Gluten-free diets tend to be similar in energy content to traditional diets, but more careful planning when going gluten-free may promote making healthier food choices. So from this perspective, gluten-free may promote weight loss, for reasons not directly related to gluten. Does avoiding gluten help those with the other disorders listed above? There are few properly controlled scientific studies to support many of the gluten-free claims, so it’s hard to know for sure. Another consideration is the foods that you might avoid by going gluten-free, such as breads, pastas and other grain products. Given that these foods are important dietary sources of B vitamins, fiber, iron and other nutrients in the American diet, avoidance of them may increase risk for various nutrient deficiencies.
Certainly, the incidence of celiac disease is increasing in the U.S. Current estimates are that 1:100 people may have celiac disease and some of them may be undiagnosed. For these individuals, going gluten-free is necessary and will often dramatically improve quality of life. From this perspective, the current popularity of going gluten-free is beneficial. The real question though is, how beneficial is gluten avoidance for the other 99/100 people in the U.S.?
Despite the endless stream of media hype these days (Paleo Diet, South Beach Diet, Atkins Diet, etc.), carbohydrates are not all that bad. At least not all of them.
One of the primary determinants of “good vs. bad” carbs is a measure called the Glycemic Index (GI). Simply put, the GI describes how quickly your body digests and absorbs certain carbohydrate-containing foods. Pure glucose (a simple sugar) has a GI value of 100, meaning that it is absorbed into your bloodstream very quickly. Peanuts, on the other hand, have a GI value of 10.
Are high-GI foods bad for you?
Well, it depends who you are and what your needs are. If you are an athlete who engages in prolonged intense exercise, then high-GI foods are your friends – they are the fastest way to replace your carbohydrate fuel stores and prevent the much dreaded “bonk”. But if you don’t exercise regularly, high-GI foods can be decidedly unfriendly.
High-GI foods lead to rapid spikes in blood sugar levels, which in turn lead to spikes in insulin levels. Insulin is a hormone released by your pancreas to shuttle excess blood sugar into your liver, muscles, and fat tissue. Unfortunately, insulin also stimulates an increase in blood triglycerides and LDL cholesterol, known risk factors for heart disease. Insulin spikes may also cause dramatic decreases in blood sugar, contributing to fatigue and hunger.
Low-GI foods are digested and absorbed more slowly by your body, resulting in a lower blood glucose and insulin response. Replacing high-GI foods with low-GI foods will not only reduce your risk for heart disease and perhaps type 2 diabetes, but will also help you maintain more even energy levels and prevent cravings between meals.
The take home message
High-GI foods are good and fine if you need them, but chronic consumption of high-GI foods can lead to an increased risk of heart disease and type 2 diabetes, as well as uneven energy levels and food cravings. Try to replace or combine high-GI foods with low-GI foods to mitigate your body’s blood glucose and insulin response.
Food for thought
- What foods tend to have high-GI values? What foods have low-GI values?
- When do you need high-GI foods? When/why are high-GI foods not such a good idea?
- What modification could you make to your diet with regard to glycemic index?