How does the nutritional value of dehydrated fruits and veggies compare to the produce in its more natural form?
Are the vitamins and minerals that are added to processed foods an important source of nutrients or are they surplus to requirements? Plus: are dehydrated fruits and vegetables as nutrient-rich as their hydrated state?
Nutrition Diva is hosted by Monica Reinagel. A transcript is available at Simplecast.
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Nutrition Diva is a part of Quick and Dirty Tips.
Hello and welcome to the Nutrition Diva podcast. I’m your host Monica Reinagel, and today I want to respond to a very thoughtful question sent in by a listener on the nutritional value of fortified foods.
But first, I wanted to take a moment to answer a question that came in on the Nutrition Diva Listener line.
“Hi Nutrition Diva! I recently bought my husband a dehydrator for his birthday and he is now dehydrating all of the produce in our home! How does the nutritional value of dehydrated fruits and veggies compare to the produce in its more natural form?”
All forms of food processing (including washing!) involve some nutrient losses. Even just sitting in the crisper drawer of your refrigerator or on your counter, fruits and vegetables will lose some of their nutritional value over time.
Not all nutrients are equally affected, though. Water-soluble vitamins (such as vitamin C) tend to be among the more fragile ones. Fat-soluble vitamins (such as vitamin A) are a bit sturdier. Minerals like calcium and zinc, as well as macronutrients like fiber or protein, are even less affected by processing or cooking.
Among the different forms of processing, dehydrating and freezing generally preserve more nutrients than baking or boiling. (They may even retain more nutrients than “fresh” produce that’s been sitting around for a while.)
The thing is, no matter how you process your produce, there is still plenty of valuable nutrition to be had from them. In fact, the recommendations for how many servings of fruits and vegetables you should eat are based in part on the assumption that some of them will be cooked or otherwise processed and will have suffered some nutrient losses.
Dehydrating fruits and vegetables can be a great way to keep fresh produce from spoiling before you can eat it. And for sure you’re going to get more nutrition from fruits and vegetables that you dehydrate vs those that you end up composting!
And listen: if you’re using your dehydrator to make kale chips, which you then eat instead of Doritos, who cares if a microgram or two of vitamin K gets lost in the process? You are still way ahead of the game!
The one thing you miss out on with dehydrated fruits and vegetables is the natural water content of fresh produce—which serves a variety of functions. Fresh produce, which can be up to 98% water by weight, is an important source of hydration in the diet. That water also helps fill your stomach, which can be helpful with portion control.
So, while I’m not worried about the nutrient losses involved in the dehydration process, and I’m all about reducing food waste, I’d encourage your husband to leave at least some of the produce in its undehydrated state for you to enjoy that way, as well.
(If you’d like to leave a question on the listener line, the number is 443-961-6026.)
And now, here’s Anne’s question about fortification, which came in by email:
“We are always advised that it's better to get our nutrients from food, if possible, rather than supplements. Where do fortified foods fit in—in terms of meeting our daily requirements?”
The first thing to understand is that fortification does not serve the same purpose as nutritional supplementation. Fortification programs are really more about population-wide health effects than individual nutrition. They often target nutrients that are either deficient in the food supply or widely under-consumed, pairing them with a food that is very widely consumed in order to maximize the impact.
For example, there are areas of the world where there is not a lot of naturally occurring iodine in the soil or water. In prior centuries, there were a lot of people running around the world with goiters on their necks… this is a swelling of the thyroid gland that results from iodine deficiency. Today, goiters are pretty rare (at least in developed nations) because iodine is now commonly added to table salt.
Folic acid is another case of fortification for the benefit of public health. The mandated addition of folic acid to flour and flour-based products has dramatically reduced the incidence of devastating neural tube defects in infants, which is caused by folate deficiency. Similarly, the fortification of milk with vitamin D (another nutrient that does not naturally occur in many foods) has largely eliminated rickets from the developed world.
As you can see, fortification programs can be a very effective way to address widespread health challenges. But beyond these targeted public health initiatives, food manufacturers often add nutrients to foods in order to boost their nutritional profile, which allows them to better position these foods as an important part of a healthy diet.
In some cases, fortification is used to bring a food up to nutritional parity with another one. For example, Americans have traditionally gotten a large percentage of their daily calcium requirement from milk and other dairy products. A lot of plant-based milks have calcium added to them so that they provide a similar amount to dairy milk. Even though the added calcium in these products may not be quite as well absorbed as the naturally-occurring calcium in cow’s milk, it’s certainly better than nothing!
Breakfast cereals are among the most aggressively fortified food products. Even highly-sweetened cereals can contain the equivalent of a daily multi-vitamin. But do these nutrients really impact our health and nutrition? Do they provide enough benefit to offset the negative impacts of the refined sugar?
Well, that depends. If you are eating a diet that’s rich in nutrient-dense foods, most of the added nutrients in a bowl of fortified cereal are probably surplus to your requirements. In that case, there’s not a lot of nutritional benefit to offset the added sugars.
However, for those experiencing food insecurity or who are eating a very poor quality diet (and, unfortunately, that’s a very large sector of the population), that same bowl of sugar-frosted, vitamin-fortified nuggets with milk—whether it’s part of a subsidized school breakfast program or all you can afford to give your kids for dinner—may be playing a very important role in their overall nutrition.
According to research published this year in Frontiers in Nutrition, people who eat ready-to-eat cereal (like Cheerios or Frosted Flakes) have higher intake of vitamins A, D, E, calcium, iron, fiber, and other nutrients, than those who don’t eat ready-to-eat cereal. This is largely due to the nutrients that have been added to these foods. And the differences are most dramatic in lower-income households—people who are often relying on food assistance programs like WIC, SNAP, and school breakfast and lunch programs.
Among kids aged 2 to 18 living in lower-income households, those who eat cereal get 71% more iron than those who don’t. Vitamin C is 21% higher and Vitamin E is 11% higher. And that can add up to a significant difference in terms of overall nutrient intake. You are likely to get as much iron from a bowl of fortified cereal as you’ll get from all the other foods you eat that day—combined.
Here’s Amy Cohn, Registered Dietitian and Senior Nutrition Manager for Cereal at General Mills:
“I think this research shines a nice spotlight on why ready-to-eat cereal has long been identified as a logical vehicle for fortification. Cereal is widely consumed across the lifespan, convenient, has the ability for uniform distribution of nutrients that are stable and bioavailable, and is affordable for most consumers. Not many foods can say that!”
Keep in mind that this does not apply to organic cereals, which do not have vitamins and minerals added to them. I know this may be hard for some listeners to swallow (I know I’ve choked over this myself). But a bowl of organic steel-cut oats might actually be less helpful in meeting some of those basic nutrient needs than a bowl of ready-to-eat, fortified, frosted flakes with milk.
Now, obviously, a bowl of fortified, UN-frosted flakes would also meet those needs without the added sugar. But, if the frosted flakes actually get eaten and the unfrosted ones don’t, that becomes a moot point. You might also be surprised (as I was) to learn that added sugar intake is actually slightly lower for lower-income kids that eat ready-to-eat cereal vs those who don’t.
So here’s the irony: for those with the resources and inclination to eat a healthy diet, a bowl of sugar-sweetened cereal might simply be a guilty pleasure—and one I’ll admit to enjoying once in a while. But for others, including millions of children, that same bowl of cereal may well represent the most nutritious meal of the day.
I want to just briefly mention one other category of heavily-fortified foods: expensive bars, shakes, and beverages pitched to the health-conscious crowd—who probably need them the least! In the context of a healthy, nutritious diet, this level of fortification is completely unnecessary and without any real benefit.
In other words, if you are nutrition-focused enough to buy bottled water with added vitamins, you probably don’t need the extra vitamins. And if you are actually buying expensive bottled water or meal replacement bars as a way of meeting your nutrition needs, I think you’d get a lot more benefit by investing those same resources in real, whole foods.
Thanks for listening. I’d love to know what you think about this issue of fortification—either as a public health initiative or as a matter of individual nutrition. Drop me an email at email@example.com.