The main health benefit of lettuce and other vegetables in a salad is the fiber. Salads are usually packed with fiber, which is a nutrient – just not for you! Fiber is real food for the microbiome, the trillions of bacteria that live in your gut. Fiber is also key to metabolic health. Bacteria in your gut convert fiber into short-chain fatty acids, which can regulate immune function and control inflammation.
Add different vegetables, such as broccoli and green peppers, and add beans and lentils to increase the fiber in your leafy green salad.
But the healthiest salads contain plenty of other good ingredients, such as antioxidants. Antioxidants are chemicals essential to your liver, detoxifying virtually all environmental toxins that enter the body. To perform this magic trick, your liver needs these antioxidants.
For antioxidants, try chopped colorful vegetables (the darker the better), chopped fresh fruit, herbs (fresh or dried), and spices. Then add proteins, such as free-range eggs, pasture-raised beef, fish, chicken, tofu, beans or lentils.
Add fats and fermented foods to your salad
Now put some whole fats on top – including avocado, olives, nuts and seeds. Nuts and seeds (such as chia seeds and walnuts) are packed with the anti-inflammatory alpha-linolenic acid (ALA), an omega-3 fatty acid that has been shown to reduce the risk of heart disease.
For other sources of omega-3s, try small fish, such as anchovies (often found in Caesar salads). You can also add other wild-caught fish (sardines, salmon, mackerel) or chicken (free-range chicken, pasture-raised chicken has fewer antibiotics).
Cheeses are a fantastic addition because they contain odd-chain fatty acids, which are protective against diabetes and heart disease. We’ve all been taught to avoid fats because they’re higher in calories, but dairy fatty acids are unique in that they have a specific phospholipid on their end that prevents inflammation. Just don’t use American cheese, which isn’t actually cheese. Instead, try varieties like feta, cotija, parmesan, and mozzarella.
Bonus points go to kale, cabbage and Brussels sprouts — cruciferous veggies that can increase your body’s natural production of antioxidants and boost the production of liver-detoxifying enzymes. Another bonus: fresh tomatoes contain lycopene, an antioxidant that supports eye function and prevents cataracts.
Adding fermented foods like kimchi and sauerkraut can give you a gut-friendly boost, as can homemade dressings made with natural, unsweetened yogurt. And fermented foods already contain short-chain fatty acids.
Avoid store-bought salad dressings
Okay. Now let’s talk about salad dressings. To make a great homemade dressing, focus on ingredients such as extra virgin olive oil, avocado oil, tahini, vinegar, Dijon, herbs, spices, and low sugar citrus juices (lemon, lime, grapefruit).
The oleic acid in olive oil activates the liver to produce a factor that speeds up metabolism. The acetic acid in vinegar inhibits an enzyme that breaks down starch in the mouth, reducing the amount of glucose that appears in your bloodstream. Some homemade dressings get extra antioxidants from spices and seasonings like ginger, garlic, turmeric, thyme, and oregano.
But the same cannot be said about most store-bought dressings. Store-bought versions are often made with canola and soybean oils, which are packed with linoleic acid, an inflammatory omega-6 fatty acid.
They can also sneak in large amounts of fructose (the sugar molecule), in the form of cane sugar, high fructose corn syrup or honey – which harm the mitochondria, the energy-producing factories that power each of your cells. When your mitochondria aren’t working properly, your blood glucose and insulin rise, and your liver has no choice but to convert the fructose into fat — fueling fatty liver disease and insulin resistance, and potentially increasing your risk of developing heart disease, cancer and diabetes.
You might be surprised how common it is for sugar to sneak into bottled dressings. For example, high fructose corn syrup is the second ingredient in Kraft’s Creamy French dressing, which contains five grams of added sugar. And watch out for fat-free dressings — Ken’s Sundried Tomato Vinaigrette, for example, has 12 grams of added sugar.
Store-bought dressings can also contain ingredients that are bad for your gut and the trillions of bacteria that reside there. These bacteria send chemical signals to your brain asking to be fed. If you don’t feed your bacteria, they actually start feeding on you — they take the mucin, a protective coating, right off your intestinal cells. Over time, this can lead to irritable bowel syndrome, inflammatory bowel disease, and altered gut permeability, which some people call “leaky gut.” It can also cause systemic inflammation.
Store-bought dressings often contain emulsifiers, such as carboxymethylcellulose, polysorbate-80 or carrageenan, which keep fat and water from separating – and can dissolve that protective mucin layer in your gut. Those pesky added sugars can also cause bad microbiome bacteria to multiply, potentially leading to gastrointestinal upset, gas, bloating, diarrhea and inflammation.
Croutons and crunchy things
But that doesn’t mean you should skip the dressing. Studies have shown that fats — such as in avocados — actually help your body absorb the nutrients from some vegetables. The key is to choose the right ingredients and, ideally, make your own dressing at home.
It’s also a good idea to stay away from “crispy” things (like fried onions and tortilla strips), which are often fried in seed oil at high temperatures, which can cause the buildup of trans fats and acrylamide, a known carcinogen. I would also suggest being careful with dried fruit; some varieties and brands coat them in sugar to make them sweeter and tastier.
And finally, watch out for processed bread. A Caesar salad isn’t a Caesar salad without croutons, but commercial croutons are usually loaded with preservatives, sodium, and vegetable oils. Bake your own croutons or combine your salad with a slice of sourdough bread. But please don’t eat the fried tortilla bowl.
Robert H. Lustig is professor emeritus of pediatrics at the University of California San Francisco and the author of “Metabolic: The appeal and lies of processed foods, nutrition and modern medicine.”
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