Sometimes you feel nauseous and you just can't figure out why. Maybe you're allergic to something, maybe something that you ate earlier that day just did not agree with your stomach. There are some foods that you might consider "healthy foods" that could actually be risky for your health.

1. Tuna

salmon, fish, seafood, fillet, trout, sashimi, steak, meat, lemon, sushi, salmon steak, smoked salmon
Jonathan Chan

Sometimes tuna can be contaminated with scombrotoxin. Scombrotoxin is a foodborne toxin that can cause a mild form of foodborne intoxication when ingested in high quantities.

2. Cheese

wine, dairy, cheddar, dairy product, milk, cheese
Katherine Hong

Nausea after eating dairy may be a symptom of mild lactose intoleranceBetween 30 and 50 million people in the US have some degree of lactose intolerance, according to the Ohio State University Wexner Medical Center.

3. Chicken

turkey, meat, chicken
Helena Lin

Chicken should always be cooked properly to avoid Salmonella bacterial infections. According to the CDC, antibiotic use in food animals can result in resistant Salmonella. It is also important to buy free-range chicken as a safer option.

4. Soy

beer, soy sauce, sauce
Sydney Rosenstein

Thousands of studies link soy to malnutrition, digestive distress, immune system breakdown, thyroid dysfunction, cognitive decline, reproductive disorders, and infertility — even cancer and heart disease.

But you don't have to stop enjoying your sushi. For a safer option, consume fermented soy products that are digestible, such as miso, tempeh, natto, or tamari. 

5. Eggs

egg yolk, chicken, egg
Jocelyn Hsu

This breakfast favorite has caused many outbreaks due to Salmonella bacteria. The bacteria can lurk inside the egg, so proper cooking is vital. And refrigerate eggs before using them.

6. Oysters

seafood, shellfish, oyster, fish, lemon, mussel
Catherine Van Helden

According to CDC, eating raw oysters can is dangerous for certain groups of people. A bacterium called Vibrio vulnificus that's in some oysters can potentially cause nausea or even disease. 

7. Berries

pasture, sweet, berry, strawberry
Becky Hughes

Berries contain antioxidants and other health benefits that far outweigh the risks of eating them. In 2014, strawberries ranked Number 2 for their pesticide content, while blueberries ranked Number 23. Berries are something to buy organic, as they can be risky to eat otherwise.

8. Tomatoes

tomato, pasture, vegetable
Luna Zhang

This one may be a relief for all the tomato haters out there. This summer favorite has been linked to many different forms of food-borne illness. Once tomatoes enter a household, bacteria may take over. 

9. Potatoes

tuber, carbohydrate, vegetable, pasture, potato
Emily Palmer

Potatoes have a high glycemic index, meaning they might dramatically impact your blood sugar.  Because of this, eating potatoes in large quantities or on their own might increase your risk of blood sugar imbalances and poor appetite control. Eat your French fries, but do it sparingly. 

10. Leafy Greens 

parsley, salad, vegetable, lettuce
Dea Uy

Your mom probably always told you to eat your greens, but it turns out that salad isn't as healthy of a food as you think. Greens such as lettuce, endive, kale, and watercress have caused 8,836 reported cases of illness between 1998 and 2008, according to the CDC.

One of these 10 "healthy" foods may be the reason why you're not feeling so hot. Next time you think about buying one of these foods, think about a safer way to consume it.