Video  | Nutrients  | Thyroid | Digestion  | Variety

Non-starchy vegetables are a great way to fill your stomach without filling your body with calories or carbs. I am often asked if there is any advantage to eating raw or cooked veggies, so I will tackle that question in this article.

Summary of Raw vs Cooked Veggies

• Some water-soluble vitamins can be lost during cooking. However, cooking may enhance the nutrient availability of other nutrients, including antioxidants. 
• Overconsumption of raw cruciferous vegetables may contribute to hypothyroidism.
• Cooking helps to break down the fibrous structures of the plants, which may be helpful for those with digestive issues. 

Raw or Cooked Veggies [Video]

In this video, you’ll learn…

• What happens to the nutrients in vegetables when they are cooked or eaten raw.
• Which cooking method is considered best.
• How eating raw and cooked vegetables affects your digestion.

There are three things we’ll consider when looking at whether or not to cook vegetables: nutrients, digestion, and variety. 

Nutrients in Raw vs Cooked Veggies

Whether you are eating starchy or non-starchy vegetables, certain nutrients, like water-soluble vitamins, are lost when vegetables are cooked. Other nutrients, however, are enhanced and more easily absorbed when cooked. 

It’s not wise to make a blanket statement that all vegetables are best eaten one way or the other. 

Spinach is a good example. In an article by Sarah Rautio of Michigan State University, she states that “cooked spinach has 245 mg/cup of calcium, while raw spinach only has 30mg/cup!”

However, cooking can destroy other nutrients like Vitamin C. She goes on to write that “Raw spinach has three times as much vitamin C than when that same amount is cooked.” 

Often, one vegetable has more of a particular nutrient when eaten raw and more of a different nutrient when cooked. For this reason, eating a variety of raw and cooked vegetables is best. 

Cooking Methods Matter

In addition, the method of cooking matters. A review study concluded that “Steaming seems to be the best method to maintain the nutritional quality of many vegetables, but that was not the case for all vegetables.” (1).

The answer to the question, ‘should I eat raw or cooked vegetables’ is not a simple one. 

Low-Carb Vegetables

To add a bit of clarity, I will present a few vegetables that are often included in a low-carb diet. This is to highlight those that are enhanced when they are cooked.

We already covered the calcium benefit of cooked spinach and see that cooking may also enhance the availability of other nutrients like iron, magnesium, and zinc while destroying bacteria that can contaminate spinach. 

Steaming asparagus, green beans, and cauliflower improves bile acid binding. This means that bile is excreted more readily from the body. Since your body uses cholesterol to make bile acids, this enhanced action reduces the level of LDL cholesterol in your blood (2).

Cooked Vegetables and Antioxidants

One of the standout benefits of cooking vegetables is the enhancement of antioxidants. 

Antioxidants are important for our health because they protect our cells and other structures from being attacked by harmful molecules called free radicals.

We see this enhanced antioxidant activity in cooked asparagus and celery (3)(4).

We also see this in cooked onions and tomatoes. Cooking onions brings out more of their flavonoids, which are antioxidants that support healthy blood vessels and cardiovascular health.

Cooking tomatoes enhances the activity of an antioxidant called lycopene, which is the pigment that gives tomatoes their red color (5).

There are also many advantages to cooking mushrooms. Not only does cooking help to release more of the antioxidants, it also lessens the risk of ingesting a potentially cancer-causing substance found in mushrooms called agaritine (6).

Raw Cruciferous Vegetables and Your Thyroid

Most vegetables can be consumed raw. However, there is evidence that overconsumption of raw cruciferous vegetables can contribute to hypothyroidism.

Cruciferous vegetables include bok choy, broccoli, Brussel sprouts, cabbage, cauliflower, and kale. 

These vegetables contain goitrogens, which are substances that have the potential to reduce the production of thyroid hormones. The amount you need in order to eat to reach a detrimental level is in question. 

For instance, a study determined that in order to avoid impaired thyroid function, you should limit your consumption of raw kale and Brussel sprouts to no more than 2 pounds or 1 kg per day. This is a rule that most of us would not have trouble living by (7).

There’s no need to be afraid to eat small amounts of raw cruciferous veggies, but if you are concerned, cook cruciferous vegetables before consuming them. This will limit the effects of the goitrogens.

Digestion of Raw vs Cooked Vegetables

As for digestion, cooking helps break down the fibrous structures of the plants. If you have digestive issues, cook the vegetables until they are tender. This is a good way to get the micronutrient value of the vegetables without digestive discomfort. 

Variety is a Consideration When Choosing Raw vs Cooked Veggies

Lastly, consider variety in your diet. It is nice to have alternatives, so having salad and cooked veggies during your day a great way for you to stay full all day long without being bored with your food choices. 

If you are wondering how to include both raw and cooked veggies in your daily diet, download a copy of my free 0123 strategy.

The 1 and 2 of the strategy are all about raw and cooked vegetables.

Don’t Forget to Add Fat

When eating veggies, don’t forget the fat!

The fat-soluble vitamins and antioxidants that occur naturally in vegetables are best absorbed when eaten with fat.

Don’t feel guilty about adding an acceptable cooking fat like avocado oil or butter to your cooked vegetables or full-fat dressing on your salad.

References: 

(1) Fabbri, Adriana DT, and Guy A. Crosby. “A review of the impact of preparation and cooking on the nutritional quality of vegetables and legumes.” International Journal of Gastronomy and Food Science 3 (2016): 2-11.

(2) Kahlon, Talwinder S., Mei-Chen M. Chiu, and Mary H. Chapman. “Steam cooking significantly improves in vitro bile acid binding of beets, eggplant, asparagus, carrots, green beans, and cauliflower.” Nutrition research 27.12 (2007): 750-755.

(3) Fanasca, Simone, et al. “Antioxidant properties of raw and cooked spears of green asparagus cultivars.” International journal of food science & technology 44.5 (2009): 1017-1023.

(4) Jiménez‐Monreal, A. M., et al. “Influence of cooking methods on antioxidant activity of vegetables.” Journal of Food Science 74.3 (2009): H97-H103.

(5) Dewanto, V., Wu, X., Adom, K. K., & Liu, R. H. (2002). Thermal processing enhances the nutritional value of tomatoes by increasing total antioxidant activity. Journal of agricultural and food chemistry, 50(10), 3010-3014.

(6) Hashida, C., et al. “Quantities of agaritine in mushrooms (Agaricus bisporus) and the carcinogenicity of mushroom methanol extracts on the mouse bladder epithelium.” [Nihon koshu eisei zasshi] Japanese journal of public health 37.6 (1990): 400-405.

(7) Felker, Peter, Ronald Bunch, and Angela M. Leung. “Concentrations of thiocyanate and goitrin in human plasma, their precursor concentrations in brassica vegetables, and associated potential risk for hypothyroidism.” Nutrition reviews 74.4 (2016): 248-258.

About the Author:

Dr. Becky Gillaspy, DC graduated Summa Cum Laude with research honors from Palmer College of Chiropractic in 1991.