成人VR视频

What is it like to teach a class of more than 20,000 students? I don鈥檛 know, but I鈥檓 about to find out. Colleagues David Harpp and Ariel Fenster and I have been selected to offer 成人VR视频鈥檚 first 鈥渕assive open online course,鈥� known in the trade as a MOOC.

It鈥檚 a brave new world out there when it comes to education. Students no longer have to be in the same room as the professor, or even in the same city or country, thanks to the advances of the electronic age. Food for Thought (EdX Chem 181x) will attempt to satisfy the increasing hunger for knowledge about our food supply and its connections to health. We will explore the nuances of nutrition, demystify food additives, take a critical look at sweeteners, pesticides and genetically modified foods, examine the ups and downs of weight control, investigate the links between diet, cancer and heart disease, cope with the problems of food-borne ailments and even foray into the kitchen for some cooking tips and wine tasting. We will try to make it all go down with the proverbial spoonful of sugar. Only proverbial, of course, because as we will point out, sugar can be quite bitter as far as health goes.

Given our backgrounds in chemistry, it probably comes as no great surprise that my colleagues and I have a long-standing interest in food and cooking. After all, food is nothing more than an amazing collage of chemicals, and cooking just boils down to altering them in some fashion to achieve a change in texture and flavour. Food, of course, is also the source of everything we are made of, so there can be no question that what we eat has an impact on our health. But determining the nature of that impact is a difficult and often confusing undertaking. How can it be anything else? We are introducing an incredibly complex array of chemicals, namely food, into the human body, the most complex machine on the face of the Earth. A simple cup of coffee, for example, contains hundreds of compounds that are set to engage in numerous biochemical reactions as they cruise through our system. Indeed, given such complexity, it鈥檚 quite amazing that we know as much as we know.

And as time marches on, the complexity increases. Consider the case of blood cholesterol. It is connected to heart disease somehow, but just how is a matter of debate. Early research focused on total cholesterol because that was the only available measurement. Then we learned that cholesterol was transported through the bloodstream via high-density lipoproteins (HDL) or low-density lipoproteins (LDL), with the former removing excess cholesterol and the latter depositing it in arteries. We were inundated with information about 鈥済ood鈥� cholesterol and the nefarious 鈥渂ad鈥� cholesterol, measurement of which was seen to be a better indicator of risk. And the most recent research indicates that LDL doesn鈥檛 really tell us much 鈥� it is the size of the LDL particles that matters. You can have the same LDL measurement, but if your LDL particles are large and fluffy, seemingly there鈥檚 no problem. However, if they are small and numerous, you鈥檇 better do something about it. But what? That isn鈥檛 clear, although many researchers point a finger at refined carbohydrates as a factor in small LDL particle formation. Further refinements will surely come. The particular type of 鈥渁polipoprotein鈥� that binds cholesterol in small-particle LDL may well be the next determinant of risk to be discovered, posing the problem of what to do about it. It seems our ability to acquire information is outstripping our ability to interpret it.

The crux of the problem with food issues is that what we knew yesterday may not mesh with what we know today, which in turn may be superseded by knowledge that comes to light tomorrow. On many occasions after my public lectures, I鈥檝e been approached by former students asking how it is that 鈥渂ack then鈥� I spoke in an optimistic fashion about some supplement 鈥� vitamin E, for example 鈥� whereas now I鈥檓 much more pessimistic about its possible benefit. The implication is that, at least when it comes to food, scientific advice has to be taken with a grain of salt, because it is constantly changing. Actually, I would be more concerned if my views today were the same as they were decades ago, because that would imply a lack of progress in research. Nutritional recommendations are indeed changing in step with new findings, including how many grains of salt we should be consuming, but admittedly in the race for certainty the finish line seems to always be receding. The only certainty about food is that you can鈥檛 survive without it.

So eat we must, but the question most of us would like answered is: Eat what? And that is one tough cookie! Depending on which 鈥渆xpert鈥� has climbed up on his or her soapbox, we should either embrace or avoid meat, fruit, soy, grains, saturated fats, polyunsaturated fats, farmed fish, organic food, dairy products, genetically modified ingredients, raw foods or cooked foods. All these insights come with references to various studies, but of course not all studies are of equal quality. These days, with appropriate cherry-picking, it is possible to find some study that will back virtually any point of view.

Our task as we tackle Food for Thought is to try to wade through the nutritional quagmire and make some sense of the overwhelming amount of information available. Unfortunately, in some cases the data is undecipherable and the conclusion has to be that there is no conclusion. In other instances, it is possible to separate the wheat from the chaff and conclude whether recommendations such as avoiding wheat are science-based.

So why don鈥檛 you join the more than 20,000 people from over 150 countries who have already signed up to accompany us on this new and exciting journey? It is totally free, with absolutely no obligation, and it starts on Wednesday. All you need is a dose of curiosity and access to the Internet. For complete information, visit bit.ly/ILc9DY.

Dr. Joe Schwarcz