Wheat has been the staff of life, and the source of our daily bread for centuries. Here in the Mill City, wheat played a pivotal role in our early economic development. The milling of wheat made Minneapolis a boom town in the 1880s, establishing a great city on the river. But these days, wheat seems to be under a cloud. Gluten-free foods are multiplying on store shelves and in restaurants, and everyone knows someone who is avoiding wheat and gluten. Amid all the confusion, we turned to experts for the science behind this issue. Find out how much you know about the topic.

1. Gluten is:

a) A food additive.

b) A protein present in certain grains.

c) High in carbohydrates.

The answer is b. For starters, it helps to know what gluten is and why we bake with it. Wheat, barley, rye and triticale are all grains that contain two forms of protein — glutenin and gliadin — which, when mixed with water, form gluten protein. Simple enough. Gluten has a unique ability to create the familiar structure we know in pasta, breads and baked goods. When a leavening agent, such as yeast or baking powder or soda, is mixed into a dough that contains gluten, it creates gas bubbles. The springy strands of gluten stretch to contain the bubbles, then harden in the heat of the oven to hold an open crumb. If you take a gluten-free flour, such as rice flour, and mix it with baking powder and water, and put it in the oven, all the bubbles will rise up through the batter and pop on the surface, leaving a brick of baked flour behind.

2. The number of people with celiac disease is:

a) A booming epidemic.

b) Going up a little.

c) About the same as always.

The answer is b. In the past 35 years, nationwide celiac diagnoses have risen from 0.21 percent in 1975 to 0.91 percent in 2000. That is a tripling of the rate, but still under 1 percent of the population, or about 3 million people. This rise parallels similar increases in all immunological diseases, such as multiple sclerosis, Crohn's disease, Type 1 diabetes and asthma. There are many theories regarding the increase. Dr. Alessio Fasano, director of the Center for Celiac Research at Massachusetts General Hospital for Children in Boston, says that many people have the genetic predisposition to develop celiac, but for some reason don't. One possibility, he says, is the bacterial balance of the gut. Having and maintaining a healthy balance of good bacteria in the gut may be protective against developing celiac disease. Once you have celiac, the only treatment is to stop eating gluten, and you remain celiac for life.

Julie Miller Jones, a retired professor of food and nutrition at St. Catherine University in St. Paul, also looks to the gut for some clues. "I think the rise in problems has more to do with the gut microbiome and poor digestion. You also have to look at how many people are taking antacids, which means that they have less acid to digest the proteins in food. If you have a less than healthy diet already, and add antibiotics and antacids, you may be causing a problem." Unlike celiac, wheat allergies can come and go. Less than 1 percent of the population suffers from allergies to wheat.

3. A growing group of people are considered to have non-celiac gluten sensitivity. This is:

a) Well understood and easy to diagnose.

b) Still controversial.

c) A fad.

The answer is b. According to Fasano of the Center for Celiac Research, up to 6 percent of the population may have gluten sensitivity. These are people with symptoms similar to celiac disease, but who do not test positive for celiac. This is still controversial, and some experts disagree. There are currently not the same kind of widely approved diagnostic tools for this that there are for celiac. "We do not have biomarkers. It is a work in process," said Fasano. "All we know is that people have symptoms, we take gluten away and they feel better. We put it back, the symptoms come back." For people suffering from digestive problems, another culprit in wheat, called FODMAPS (Fermentable Oligosaccharides, Disaccharides, Monosaccharides and Polyols), may be causing the problem, not the gluten. It is important to have a doctor rule out celiac disease before self-diagnosing a sensitivity because celiac tests are most accurate when you are consuming gluten.

4. Many of our current ills, from heart disease to allergies, are made worse by chronic inflammation in the body. Chronic inflammation is caused by:

a) Eating grains of any kind, including wheat.

b) The immune system responding to a perceived irritant or injury.

c) Not eating enough yogurt.

The answer is b. Inflammation is the body's response to injury or invasion. For people who are celiac or allergic to wheat, eating wheat would trigger inflammation. "Excess weight is a major cause of inflammation, and not eating enough of the fruits, vegetables and whole grains that contain anti-inflammatory chemicals doesn't help," said Jones of St. Catherine University.

For the rest of us, it looks like eating whole grains actually fights chronic inflammation. Whole grains do this by feeding the beneficial bacteria in our guts, which helps us to keep our digestive process from fueling added inflammation. Eating yogurt does add probiotics to your diet, but whole grains are effective prebiotics. "Whole grains contain many of the fibers that beneficial bacteria thrive on," said Jones.

5. How much wheat in the U.S. is genetically modified?:

a) It's all genetically modified to contain lots of gluten.

b) None of it is genetically modified and the gluten is about the same as a century ago.

c) None of it is genetically modified, but it's higher in gluten than a century ago.

The answers is b. None of the wheat available commercially in the U.S. is genetically modified. Wheat is an important export for American farmers and they have worked to keep wheat GMO-free so that other countries that ban GMOs will buy it. It's true that any food labeled organic is not GMO. According to Brett Carver, regents professor at Oklahoma State University, pre-1940s bread wheat ranged from 11.7 percent protein (gluten) in the Southern states and 13.4 percent protein in the North, and those levels have not changed. Today's wheat has 98 percent of the same genes as ancient wheat. Plants can only express proteins that they have the DNA code to produce, so they can't make gluten that is different from the gluten of their ancient predecessors.

Wheat has been bred and hybridized, like all other food plants. Just like the cantaloupe or kale you grow in your garden, it has been bred to have higher yields, better pest resistance, and to grow well in a certain region. "All the breeding that has been done was to increase the number of seeds per plant, and make the stems shorter, not to increase the gluten," said Jones. There is a revival of interest in ancient wheats, such as einkorn, farro and spelt, as well as heritage wheats, like Red Fife, in part because they are genetically simpler. Many people believe that they are also easier to digest.

6. Wheat and obesity are related because:

a) Wheat is in bread and it is making us fat.

b) Eating wheat causes blood sugar to spike.

c) Whole wheat is actually good for maintaining a healthy weight.

The answer is c. Of course, if you eat too many calories, you will gain weight. But there is no proof that calories from wheat are any more fattening than from any other food. White and whole-wheat breads, like all carbohydrate foods, do have an impact on blood sugar, but it is comparable or less than potatoes or white rice. In real life, you combine bread with high fiber vegetables and the fats from your meal, and the bread has less of an effect on blood sugar than it would alone.

"It's also important to eat more of your wheat in whole form, with the bran and germ intact. We have eaten wheat since biblical times, and for the vast majority of people it is a healthy food. Consumption of whole grains is associated with healthy body weight," said Leonard Marquart, associate professor of food science and nutrition at the University of Minnesota.

According to Jones of St. Catherine University, a sensible diet is probably the cure to the obesity problem. "Overconsumption of too many calories and too little physical activity causes obesity. The classic Mediterranean diet, with grains at the base, didn't cause obesity. If you eat Ding Dongs and doughnuts, you get too many calories and very few nutrients. It's too simplistic to blame obesity on wheat."

7. Our consumption of wheat has changed.

a) We eat way more of it these days.

b) We eat less than we have in the past.

The answer is b. In the U.S., average wheat consumption in 1830 was about 170 pounds per year, and it grew to a peak of 230 pounds per year in the 1870s. Consumption dropped consistently after that, down to 110 pounds in the early 1970s, when it rose again to around 140 pounds. It's dropped a bit since then. If wheat alone caused obesity, Americans in the 1870s would have had an obesity crisis, but that didn't start until 1980.

Americans eat less wheat than many other countries. The French eat twice as much wheat, but have one-third the rate of obesity. Australia and Turkey have the highest per capita consumption of wheat.

Our consumption of gluten, on the other hand, has increased a bit, because there has been a move to add pure gluten flour to processed foods to boost protein. Adding gluten flour to whole-wheat bread doughs helps make them rise higher and bake into lighter loaves.

8. Many people are concerned about the use of chemicals on their food.

a) Wheat is drenched in herbicides.

b) Wheat is about average in herbicide use.

The answer is b. There is a story going around the Internet stating that wheat farmers use large quantities of glyphosate herbicide at harvest, to effectively kill the wheat plant so it is easier to harvest. According to Jochum Wiersma, associate professor in the Department of Agronomy and Plant Genetics at the University of Minnesota, about 2 percent of the U.S. wheat crop may be sprayed with herbicide a week before harvest. This is only done in Minnesota and the Dakotas, and only as a last-ditch effort to dry the plants when conditions are too wet to harvest. It is an expensive strategy that is employed to save a crop that might otherwise be lost. Most conventional wheat is not any more heavily sprayed than other conventional crops. If you want to avoid herbicides, you can always buy organic wheat.

9. Wheat contains chemicals that trigger opioid receptors in the brain, making it:

a) Highly addictive and a binge food.

b) Kind of fun to eat.

c) Just like milk, spinach and a few other foods.

The answer is c. In a 1979 study, a certain wheat protein, called gliadorphin, after being broken down to its component peptides, induced opiate-like responses in rats. These experiments didn't use wheat foods, but extracted peptides. Scientists say that the human body is probably not able to absorb this chemical in a form that could actually make it to the brain or nervous system. So far, no similar experiments have been done using actual wheat in foods or on humans. Similar opiate-like chemicals are in milk, rice and spinach.

Wheat has been a part of our diet for centuries, and likely always will be. As scientists look more at wheat and gluten, some of us find good reason to give them a pass. Though sorting out the role of diet in health issues can be frustrating, the coming years will undoubtedly bring some much needed answers.

Robin Asbell has written six cookbooks, including "The New Whole Grains Cookbook" and "Gluten-Free Pasta." She teaches cooking in the Twin Cities.