What Defines a Functional Food?
According to Health Canada, a functional food resembles or is a conventional food, eaten as part of a regular diet, and is shown to provide physiological benefits or lower the risk of chronic disease beyond fundamental nutritional roles. Potatoes, particularly certain types and how they are prepared, align with this description by offering a range of beneficial compounds.
The Role of Resistant Starch in Potato Functionality
Resistant starch (RS) is a type of starch that bypasses digestion in the small intestine and is fermented in the large intestine by beneficial gut bacteria. This fermentation is vital for gut health and provides several advantages:
- RS acts as a prebiotic, supporting the growth of beneficial gut bacteria like Lactobacilli and Bifidobacteria.
- Fermentation produces short-chain fatty acids (SCFAs), notably butyrate, which is a main energy source for colon cells.
- RS is associated with improved blood sugar management and reduced insulin resistance.
- It can also enhance feelings of fullness, potentially aiding weight management.
To increase resistant starch in potatoes, cook and then cool them. This process, called retrogradation, makes the starch more resistant to digestion. Cooled potato dishes or reheated potatoes can therefore offer more resistant starch than those eaten immediately after cooking.
Antioxidants: The Power of Color
While all potatoes contain antioxidants, vibrant varieties like purple, red, and yellow potatoes are rich in powerful antioxidant compounds that protect against oxidative stress.
- Anthocyanins: Found in purple and red potatoes, these contribute to their color and may have anti-inflammatory, antibacterial, and anti-cancer effects. Consuming purple potatoes has been shown to lower blood pressure in a small trial.
- Carotenoids: Yellow and orange potatoes contain carotenoids like lutein and zeaxanthin, known to support eye health.
- Phenolic Acids: Chlorogenic acid, prevalent in potato peels, is linked to slowing glucose absorption.
- Vitamin C: Potatoes are a good source of Vitamin C, an antioxidant important for immunity, iron absorption, and collagen.
Other Functional Components
Potatoes also offer other functional benefits:
- Quality Protein: Potato protein contains essential amino acids. Certain potato protease inhibitors are being studied for potential weight management and antimicrobial properties.
- Essential Minerals: Potatoes are high in potassium, crucial for heart and nerve function, and also provide magnesium and phosphorus.
Comparative Overview of Potato Functional Properties
| Feature | White Potato | Colored Potato (Purple/Red) | Cooked & Cooled Potato |
|---|---|---|---|
| Antioxidant Content | Moderate (mainly vitamin C, some phenolics) | High (rich in anthocyanins, carotenoids, phenolics) | Moderate (varies with variety and storage) |
| Resistant Starch | Low (if eaten hot) | Low (if eaten hot) | High (due to retrogradation during cooling) |
| Butyrate Production | Moderate (fermentation of low RS) | Moderate (fermentation of low RS) | High (fermentation of high RS) |
| Potential Health Benefits | Basic nutritional support, some antioxidant effects | Stronger antioxidant benefits, potential anti-inflammatory and cardio-protective effects | Improved gut health, better blood sugar control, enhanced satiety |
The Final Verdict: How to Maximize Potato's Functional Status
The evidence suggests potatoes can be functional foods when prepared and consumed thoughtfully. Their antioxidants, minerals, and resistant starch offer benefits for gut health, inflammation, and cardiovascular health. To get the most benefits:
- Cook and Cool: For more resistant starch, cook potatoes (boiling or baking is recommended) and let them cool before eating, such as in salads or reheated.
- Eat the Skin: Much of the fiber and phytonutrients are in the skin. Leaving it on increases nutrient intake.
- Choose Colorful Varieties: Include purple, red, and yellow potatoes for more antioxidants.
- Avoid Frying: Frying adds fat and calories, reducing health benefits. Opt for baking, boiling, or steaming.
- Moderation: Enjoy potatoes as part of a balanced diet with other nutrient-rich foods.
Conclusion
Potatoes, long seen as a basic starch, contain many bioactive compounds that give them functional food potential. Their resistant starch for gut health, antioxidants for disease fighting, and essential minerals offer significant benefits when prepared correctly. Choosing colorful varieties and methods that boost functional properties can make potatoes a valuable part of a healthy diet. Research indicates the potato is a nutritional powerhouse with functional food capabilities.
