With colder weather around the corner, cold sores might start to become a problem if you’ve experienced them in the past. These painful bumps around the mouth can be embarrassing and frustrating to deal with.

Most people know of a few specific things that usually trigger their cold sores, such as illness, cold weather and stress. However, you may have also noticed cold sores popping up after you eat certain foods.

Is this coincidence, or can your diet actually trigger a cold sore outbreak? Here’s what you should know.

Understanding cold sores

Cold sore outbreaks are caused by the herpes simplex virus-1, which can remain dormant in the body for long periods of time. This virus is different from the type of herpes simplex that causes genital herpes, and it is very common because of how easy it is to spread.

Cold sores are small, painful infections that typically appear around the mouth. The sores tend to look like scabby blisters and may ooze pus. The sores themselves generally last between seven and 10 days, but the herpes simplex virus will remain in your body for life.

The link between cold sores and diet

Herpes simplex virus lays dormant in the cells until the immune system is compromised, which is why so many people get cold sores when they are stressed or sick. Then, the virus can begin to activate, causing cold sores.

When the herpes simplex virus infects your body, it takes over cells and replicates them, creating new versions of itself. Which cells the virus targets is tied to the cells’ level of arginine—a semi-essential amino acid. Arginine allows the infected cells to reproduce. Without arginine, the virus can’t cause an outbreak.

You need some arginine in your diet, since all amino acids are needed to create proteins within the body. However, if you’re susceptible to cold sores, you should try to eat foods that have a high lysine to arginine ratio—meaning, foods that have a lot of the amino acid lysine and low amounts of arginine.

Lysine helps counteract arginine in terms of cold sores, helping to prevent outbreaks.

Foods that could trigger cold sores

Because of the role arginine plays in herpes simplex virus’ replication and cold sore outbreaks, it’s important to minimize the amount of arginine you’re eating compared to the amount of lysine. When you’re trying to prevent an outbreak, you should avoid eating a lot of these arginine-rich foods:

• Whole grains like wheat bread
• Almonds and other nuts and seeds like walnuts, hazelnuts and sesame seeds
• Grape juice and red grapes
• High-sugar foods
• Peanut butter
• Orange juice
• Beer
• Chocolate
• Dark leafy greens

Another aspect of prevention is making a point to eat certain lysine-rich foods, including:

• Butter
• Cheese
• Milk
• Chicken
• Lamb
• Fish
• Apples

When choosing foods to prevent a cold sore outbreak, balance is key. You don’t need to completely avoid foods that contain arginine—you can enjoy foods that are somewhat high in arginine, but you should be sure to also eat foods high in lysine to balance the two amino acids out.

Diet and immunity matter, too

Aside from paying attention to your diet’s lysine to arginine ratio, you should also be mindful about the nutrition content of your diet overall. Eating a balanced, nutritious diet is key in bolstering the immune system, which will help you prevent cold sores from forming.

Herpes simplex virus begins to cause an outbreak when the immune system is compromised or weakened. Eating a diet filled with processed foods or one that is lacking in particular vitamins and minerals can hamper the immune system and make it susceptible to a viral takeover.

Additionally, eating lots of foods filled with sugar can weaken your immunity. Sugar hampers your body’s ability to destroy harmful pathogens, paving the way for viruses and bacteria to take over and make you sick.

Fill your diet with a mix of food types, including vegetables, fruits, complex carbohydrates and lean proteins. If an allergy or lifestyle choice prevents you from getting enough of a particular nutrient, consider taking a nutritional supplement to keep your immune system—and your entire body—in great shape.

By combining a nutritious diet with a careful balance of arginine-rich and lysine-rich foods, you’ll have a much better chance at preventing cold sores. Of course, you’ll also want to minimize your risk through other preventative measures, such as limiting stress and getting enough sleep.