Tag Archives: vitamins

The Devil’s in the Dietary Details

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Longer than many of my blog posts, this piece reflects the current state-of-the-science and contrasts the dietary guidelines put forth by the USDA to Harvard’s Healthy Plate. The principles of a sound diet, from vegetables to grains to protein, are all discussed.

Love food? Who doesn’t! Wondering what to eat? Who isn’t!

From farm to fork, what we eat matters. This is the subject of a number of courses I’ve taught over the years, including one I’m currently co-teaching at Harvard Extension School. In these classes, it’s my goal to help students understand the personal, local, and global consequences of their day-to-day food choices.  But student or not, all of us are left with the same inevitable question each evening: What should I make for dinner? One place to start tackling this ostensibly straightforward question is to consider how food impacts our individual health—that is, nutrition.

A Tale of Two Plates: USDA’s MyPlate and Harvard’s Healthy Eating Plate

Let’s first consult the current Dietary Guidelines forAmericans, published by the Department of Health and Human Services and the Department of Agriculture every five years. In fact, the USDA has been producing food guides since 1916, which have taken on a variety of shapes and messages over the decades. Many people are familiar with the 1992 Food Guide Pyramid, which quantified serving recommendations and highlighted variety, moderation, and proportion. Steps were added to the side of the pyramid to reflect the importance of physical activity in 2005, and the name was changed to MyPyramid. Serving recommendations were removed but could be personalized online across 12 different calorie intake levels (hence the “My”).

To reduce the complexity of translating the guidelines into everyday diets, the pyramid became a plate in June 2011 and now includes five food groups: four on the plate itself (fruits, vegetables, grains, and protein) and a glass labeled “dairy” (ChooseMyPlate, left). The graphic and messages of MyPlate are undoubtedly easier to comprehend than those in MyPyramid. As well, the familiar serving vessels make it simple to apply them to meals by depicting the relative proportions of key food groups.

From a nutrition science perspective, however, there are a lot of critical details missing from the USDA’s plate. These omissions beg the question: With so much not on the plate, does this new icon accurately represent the latest science of healthy eating? In other words, when does “simple” become “simplistic”?

Enter the Healthy Eating Plate, published by the Harvard School of Public Health’s Department of Nutrition in in September 2011.

Both Plates Star Plant Foods

As you can see, Harvard’s rendition is similar to the USDA’s MyPlate in many respects. Fruits and vegetables comprise half of both plates, reflecting the importance of a plant-based diet in reducing risks of a number of chronic diseases. Unquestionably, one of the single best things you can do for your health is consume more vegetables and fruit, which are nutrient-dense sources of vitamins, minerals, water, and fiber. However, the Harvard plate also points out that variety and color matter: plants have different bioactive components that have diverse health effects. Thus, the richer the palate of your plate, the greater the nutritional benefits.

Fruits are also much sweeter than most vegetables and are a source of sugar. They should therefore be consumed in smaller quantities than vegetables. This is an important point, and the placement and proportions of the vegetable and fruit wedges on Harvard’s plate better represent this distinction compared to MyPlate.

But do I need to eat my vegetables steamed? (Yawn.) And can I use salad dressing? (Please?) Harvard’s version addresses these questions with its cruet of vegetable oil in the top corner. The picture and text also make clear that all fats are not created equal. So don’t feel guilty for adding healthy fats to your diet. They add flavor, enhance absorption of nutrients, and have been shown to decrease your risk of cardiovascular and other diseases when substituted for saturated fats, trans-fats, and carbohydrates.

Grains and Protein: A Few Caveats

The two plates also share the grains and protein categories, but Harvard’s plate adds the qualifiers “whole” and “healthy.” Are these additional terms necessary? The short answer is yes. Whole grains preserve the nutritional richness of the entire kernel, which includes fiber and a host of vitamins and minerals. (For more on whole grains, search my blog for recipes like this one and start with this piece.) Refined grains, in contrast, are mainly composed of starch, which acts much like table sugar when digested and has been associated with increased risk of insulin-related diseases such as type 2 diabetes and heart disease. “Healthy” protein sources tend to be lower in saturated fat and sodium and higher in polyunsaturated fats and fiber.

All that said, MyPlate was designed to present the basics of healthy eating in an accessible way but was not intended to provide specific dietary advice. In fact, if you visit the USDA’s website, you’ll find many more details and great tips on which grains and proteins are healthier choices that are largely consistent with the messages on Harvard’s plate. Thus, the differences between MyPlate and the Healthy Eating Plate are less about the coherence of the science and more about the level of complexity that is needed to best inform individual food choices.

Dairy Matters: It’s Not a Moo(t) Point

One area where MyPlate and the Healthy Eating Plate differ on the science is in the quantity of dairy in a healthful diet. Notice the different beverage cut point between the two plates? Dairy is a rich source of nutrients such as calcium, which is critical for bone health. Calcium can be obtained from other foods, however, and scientists disagree about how much dairy is needed in human diets, if at all, and whether dairy intake is associated with health risks. There are also multifarious matters associated with milk production, including farming conditions for both cattle and workers, and the putative influence of the dairy industry and lobbies on the dietary guidelines. And I would be remiss if I didn’t mention that many people have ethical and moral issues concerning the consumption of animal products.

Harvard’s plate, on the other hand, recommends limiting dairy intake and instead emphasizes the benefits of water. Water is essential for life and, while much of what we need for hydration is obtained in the water-containing beverages and foods we consume, it’s a great go-to beverage that quenches your thirst and helps you feel satiated without adding calories. Many studies have also found that coffee and tea are quite healthful and help meet water needs. And most scientists agree that consuming sweetened beverages like soda and fruit drinks adds significant sugar and calories to a diet and should be minimized or omitted, especially given the current obesity epidemic.

So for all of the aforementioned reasons, dairy is probably one of the more difficult topics in nutrition. The politics and polemics surrounding food production and dietary guidelines certainly don’t help matters. It’s also a wonderful example of how what we eat matters far beyond our individual health, an issue neither plate addresses.

USDA’s MyPlate: A Step Forward

I believe that MyPlate is in many ways a step forward, despite the omission of healthy fats and arguable over-emphasis on dairy. It shows individuals what their plate should actually look like in an accessible, familiar way. Plant-foods are appropriately emphasized. And, although not explicitly stated, the guidelines behind the graphic are based on sound science. If a majority of Americans followed just the vegetable and fruit guidelines, for example, it would be a major advance in health and nutrition.

However, the “go-to” graphic that represents what we should be eating should not leave out key qualifying terms (such as “whole” grains) that rely upon the consumer to fill in the gaps in an environment dominated by media sound bites and misinformation. MyPlate thus crosses the line from simple to simplistic, in my view, and even has the potential to mislead. As with most things, the devil is in the details.

Yes, Harvard’s Healthy Plate is more complex than MyPlate, but it is actually a remarkably succinct summary of the current state of nutrition knowledge and provides necessary information to guide healthy food and beverage choices that will improve your health and decrease your risk of many chronic diseases.

Translating Science to Your Dinner Plate: Help is Here!

All that said, if your plate brims with vegetables and fruit, whole grains, and healthy fats and proteins, you’re heading in the right direction. To be sure, there are many more reasons why what we eat matters–such as the local and global impacts of our food choices. These are topics that are worthy of your consideration when choosing what to eat, and I discuss these broader concepts in nutritional ecology here on my blog as well. For help in applying sound nutrition science to your own plate in delicious and sustainable ways, from farm to fork, I hope you continue reading my blog so I can help you in your journey. This is, in fact, my mission. You’ll undoubtedly improve your own health. And, acting together, we just might even change the world, one delectable bite at a time.

Originally published on Harvard University Extension School’s blog on September 30, 2011.

P.K. NewbyDr. P. K. Newby is a nutrition scientist and educator with expertise in the prevention of obesity and chronic diseases through diet and the relations between agriculture, food production, and public health. She brings together her passions for food, cooking, science, and sustainability through her writing and videos to help people eat their way towards better health, one delectable bite at a time. If you like what you see here at The Nutrition Doctor is In the Kitchen, please subscribe to my blog from the home page, become a fan on Facebook, follow me on Twitter, check out my food porn on Pinterest, watch my videos on YouTube, and peruse my recipe page for soups, salads, seafood, sweets, and more. Thanks for reading!

Should’ve Had a V-8?

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I have some unfinished business I need to complete regarding vegetable juices, and this is the subject of today’s post. It’s almost as thrilling as maple buttercream and pan seared bluefish, I know. (Not served together! Geesh.) In all seriousness, though, I was in fact pretty darn excited when I made homemade vegetable juice, so I’m glad to have the opportunity to revisit the issue.

Homemade Vegetable Juice: Still Consumed in the 21st Century

Truth be told, I have no idea how many people actually drink tomato juice and/or whatever other vegetables juices in the year 2011 – and there are quite a few on our crowded supermarket shelves. I imagine it was more popular a few decades back: in an episode of Mad Men c.1960 a woman ordered a tomato juice apéritif, which came served with a lemon wedge. I laughed when the waiter brought the juice over because it looked exactly like the juice I served up on the video I posted a few weeks back. (See picture, right, and you can also click here to watch how I made it.)

Nevertheless, at least one student in my class drinks it – hence this email – and I know some people enjoy bloody or virgin marys with brunch, so in this post I’ve provided some things for you to consider if you include vegetable juices in your diet. (I’ll save the fruit juice discussion for another time, although some of the issues are the same.)

Let’s Get Quantitative

Yes, I do love saying that, and it just may become one of my catch phrases. Reading nutrition information and understanding how things fit together in a healthy diet has a quantitative element to it, and one of my goals is to help you become better acquainted and more comfortable with these numbers. Nutritional literacy, let’s call it, which is really just a subset of scientific literacy. Knowing your numbers is especially important when it comes to watching your weight.

Before you roll your eyes, if you’ve been following my blog, you’ve read enough at this point to understand that it’s not always about numbers and nutrition with me. That would be no way to go through life. See previous buttercream reference, for example, with many more yummy things to come as we approach holiday baking season. So bear with me today, because moderation, indulgence, and nutrition all come together in my world to create delicious and healthful habits that also keep your sweet tooth satisfied.

Selected Key Nutrient Values for Vegetable Juices. (Sources: Nutrition Facts panels on products.)

The Positive: Lots of Veggies, Loads of Nutrients

Most vegetable juices are a mix of lots of different veggies. For example, my recipe included tomatoes, onions, parsley, red and green peppers, and carrots and celery with their fronds. In other words, I’d need to eat all those vegetables to get the array of nutrients I obtained in just one glass of juice. Thus, there is truth in adverts that highlight the number of servings of veggies you get in a juice, which is often 2 or more. It’s not a small point, because the vast majority of people do not consume the recommended amounts of vegetables and fruits per day needed for optimum health. Do look at the ingredients list, however. Many brands are 100% vegetable juice but it will vary by company and many will include other stuff you don’t want or need.

Vegetable juices are a terrific source of many vitamins and minerals, notably vitamins A, C, and potassium; they also provide some fiber and protein (see above table) and smaller amounts of calcium and iron. Potassium is a mineral needed for fluid balance in the body and is important for maintaining normal blood pressure and heart health. And we could all use more fiber in our diet, so important for gastrointestinal health as well as chronic disease prevention. There are also lots of other bioactive components in there, like lycopene (an antioxidant especially prominent in tomatoes), and you get a whole lot more of it in one serving of juice than a single tomato. Lycopene has been associated with decreased risk of prostate cancer and improved eye health, among other health benefits.

Now, I’m not exactly sure how my juice measures up; alas, I don’t have the right instruments in my house to do this. I do know there was no sodium added during preparation, and I conjecture there were levels of vitamins a, c, and potassium at the higher ranges shown in the above table. My tasty concoction was likely higher in fiber than many brands you’d find in the store since I milled it by hand and thus retained a lot of the pulp. (If you’re not into pulp, you could strain it further when making your own though you are removing valuable fiber, much like when removing the bran and germ from the whole grain.)

Always remember that the more broadly you eat across the food supply, especially in the plant kingdom, the more nutrition you get – both the things we know about, and the things we don’t.

The Negative: Excess Sodium and Calories

We all ingest way too much salt, and it’s associated with higher risks of hypertension (high blood pressure), stroke, and heart disease. Remember that canned and processed foods are the biggest culprits, and veggie juice can therefore contribute. If you select an 11.5 oz can of Mr. and Mrs. T’s Spicy Bloody Mary Mix, for example, you’re almost at your daily limit for sodium for optimal heart health (<1500 mg/d); check out their website for all the ingredients in this particular brand.

As we observed when I examined vegetable stocks a few weeks back, the great thing is that there are low sodium options out there for you to select if you do enjoy vegetable juice and don’t want to make your own. I use store bought vegetable juice when I’m making chili or tomato soup; I can’t imagine I’d make my own all the time, especially in winter. If you do not yet read the Nutrition Facts panel when you shop, I encourage you to begin doing so to get a better handle on what you are putting into your body.

Apart from the sodium issue, it is worth noting the energy (calorie) content of veggie juices, also shown above. Due to their lower sugar content, veggie juices are generally much lower in calories compared to fruit juices and usually do not have added (not naturally occurring) sugars. But they still contain calories, and most of us already take in too many calories, especially from beverages. Plus, we often consume more than what the label tells us is a “serving.” So be aware – or, perhaps, beware – of how much you drink, and do the math as needed; many bottles are approximately 12 ounces, so multiply the above numbers by 1.5.

Importantly, our bodies are not as able to recognize satiety signals from beverages compared to foods, which are what tells our brains that we are full and should stop eating. The fiber in veggie juice helps slow digestion and can help us feel sated, but it’s still a lot easier to ingest extra calories when consuming them in liquid form (juice) compared to solid (whole plants). Of course, if energy intake is not balanced with energy expenditure, weight gain will ensue.

Summing Up: Should’ve Had a V-8?

For a number of reasons, it’s generally better to consume whole foods compared to juices, even if homemade. Literally speaking, it would be better from an energy intake (calorie) perspective to mix all my lovely ingredients together in a salad rather than blend it into a veggie juice, which delivers a concentrated source of calories quickly to the body. The salad would retain all of the same nutrients but I’d get more fiber, digest more slowly, and undoubtedly feel fuller post-prandially (after eating). As a result, I’d likely end up consuming fewer calories. Which is generally a good thing.

But, as I’ve said, it’s awfully hard to make a bloody mary that way, and a cold glass of veggie juice also made a very fine snack one day. As well, it’s quite dense in valuable nutrients, can help meet vegetable and fiber needs, and there are some good choices on the market if you don’t feel like making your own. So, if drinking veggie juice has been a good way to get some extra veggies in your diet and you enjoy it, I’d say go for it. To recap: read the ingredient list, look at the sodium and calorie content, and consume as part of a calorically balanced diet.

You now have about 10 months to get ready for making homemade vegetable juice with me next summer, because I forgot to mention a very important positive, which is taste. Nutrition is one thing, but taste is key, is it not? And, as with so many things, store bought simply does not compare to the fresh and tangy flavors and personal satisfaction you experience from making it on your own.

P.K. NewbyDr. P. K. Newby is a nutrition scientist and educator with expertise in the prevention of obesity and chronic diseases through diet and the relations between agriculture, food production, and public health. She brings together her passions for food, cooking, science, and sustainability through her writing and videos to help people eat their way towards better health, one delectable bite at a time. If you like what you see here at The Nutrition Doctor is In the Kitchen, please subscribe to my blog from the home page, become a fan on Facebook, follow me on Twitter, check out my food porn on Pinterest, watch my videos on YouTube, and peruse my recipe page for soups, salads, seafood, sweets, and more. Thanks for reading!