with Dr. Kathleen Regan, ND

Oral herpes is a virus (HSV-1) that can become chronic in the body by remaining dormant in the nervous system. It is able to hide from the immune system in this way however, when immunity is low, it creeps back down the nerves to the skin where it causes cold sores. Keeping our immunse system in tip top shape is one way we can fight this virus but watching our dietary intake of arginine and lysine can also help.

Arginine, an amino acid, has many health benefits (ex., injury recovery, cardiovascular). BUT it is not so helpful when it comes to herpes. Arginine is required for the replication of the herpes virus and when eaten in large quantities – it can increase our susceptibility. Lysine, another amino acid, inhibits viral replication of herpes by competing with arginine.

These findings have led to the common use of lysine to treat cold sores. Seven randomized, double-blind, placebo-controlled studies (see references) have examined the effectiveness of lysine in preventing outbreaks of oral herpes and reducing the severity of outbreaks that do occur. Six of these studies found lysine to be effective in preventing or decreasing outbreaks, and only two found that lysine reduced the severity of out-breaks. It seems that lysine in sufficient concentrations relative to arginine suppresses reactivation of cold sores BUT does work best as a preventative medicine.

Those of you who are plagued by cold sores know the familiar tingling feeling that warns you an outbreak is on its way. Loading up on lysine at this time is understandable but may not be as effective as taking lysine as a daily supplement or increasing your dietary intake of lysine relative to arginine. Lysine will reduce the frequency and severity of attacks in dosages of 1,500mg/day. Some research suggests that the dosage should be higher at 3,000mg/day.

And what about the lysine you get from your daily diet? The average adult diet supplies 6–10 g/day of lysine. Lysine, unlike arginine, cannot be made within the body – it is an ‘essential amino acid’. If lysine is not consumed in the diet in adequate quantities relative to arginine,you may become more susceptible to cold sores. Therefore, it is important to consume a diet that is rich in lysine:arginine ratio.

The Mediterranean diet is one such diet. It emphasizes grains, but also emphasizes fruits, vegetables, cheese, yoghurt, and fish, all foods high in lysine and low in arginine. This is generally attributed to omega-3 fatty acids in fish. Fish have a high lysine to arginine ratio. Dairy products also have a high lysine to arginine ratio. Conversely, unlike fish and dairy products, tofu has a high arginine to lysine ratio. Looking for something a bit more specific?

The key is to consume foods that are high in lysine relative arginine and to avoid foods that are high in arginine overall – NOT to cut out arginine all together (as that would be almost impossible AND unhealthy!!) Below is a list of foods that looks at lysine relative to arginine in common foods.


Arginine food sources Arginine content (grams /100 gram of food)
Plant products
Peanuts, Spanish 3.13
Peanuts 3.09
Almond nuts 2.47
Seeds, sunflower seed kernels, dried 2.40
Walnuts, English 2.28
Hazelnuts 2.21
Lentils, raw 2.17
Brazil nuts 2.15
Cashew nuts 2.12
Pistachio nuts 2.03
Flax seed 1.93
Beans, kidney, all types, mature seeds, raw 1.46
Pecan nuts 1.18
Beans, French, mature seeds, raw 1.17
Soybeans, green, raw 1.04
Tofu, extra firm, prepared with nigari 0.66
Wheat flour, whole-grain 0.64
Garlic, raw 0.63
Muffins, blueberry, toaster-type 0.30
Onion, raw 0.10
Chocolate syrup 0.09
Animal products
Fish, tuna, light, canned in oil, drained solids 1.74
Chicken, broilers or fryers, giblets, raw 1.19
Salmon, Atlantic, farmed, raw 1.19
Shrimp, mixed species, raw 1.18
Egg, yolk, raw, fresh 1.10
Egg, whole, raw 0.82
Egg, white, raw, fresh 0.65
Pork, fresh, separable fat, raw 0.56
Milk, whole, 3.25% milkfat 0.08


Food Types and Their Lysine:Arginine Ratios
Yogurt 3:1
Cheese 2.5:1
Butter 2.25:1
Cow’s Milk 2:1
Avocado 1.5:1
Fish 1.5:1
Chicken 1.5:1
Beef 1.3:1
Egg 1:1
Cocoa 1:1
Oats, Wheat 1:1
Spinach 1:1
Corn 1:1
Carrots 1:1
Banana 1:1
Sesame Seeds 1:2.2
Flaxseeds 1:2.2
Pumpkin Seeds 1:2.2
Pecans 1:2.4
Sunflower Seeds 1:2.5
Cashews 1:4.4
Almonds 1:4.5
Brazil Nuts 1:4.8
Walnuts 1:5.4


The take home message is:

Consume foods that are high in lysine to arginine ratio including:

  • Yogurt
  • Cheese
  • Butter
  • Milk
  • Avocado
  • Fish
  • Chicken

Moderate consumption of foods that have an even arginine to lysine ratio:

  • Eggs
  • Chocolate/Cocoa
  • Oats/Wheat
  • Spinach
  • Corn
  • Carrots
  • Bananas

Avoid foods high in an arginine to lysine ratio including:

  • Nuts and Seeds

Following the mediterranean diet guidelines to prevent oral herpes:

This is a whole food diet that emphasizes fruit, whole grains and oils with adequate sources of healthy fats and proteins. The only difference is that you would avoid the recommendation for nuts. Also, if heart disease is not an issue, we recommend consuming whole fat, organic dairy products instead of ‘low-fat’.

For more information on this program please visit the Mayo Clinic outline at: http://www.mayoclinic.com/health/mediterranean-diet/CL00011. Or ask for our clinic handout.


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