Brussels sprouts is a Green-Green food. Green-Green foods are very safe to eat as a regular part of a diet.
Guideline related quotes related to Non-Starchy and Green-Green throughout Geoff Bond's publications.
Eat at least 2 3/4 lbs of mixed salad and vegetables per day, consisting of "Green-Green” and “Green” foods. Of these, at least 3/4 lb should be mixed salad. Also include at least 5 cups of “Green-Green” leafy vegetables or 2 1/2 cups of other vegetables per week. ~Paleo in a Nutshell p.102
Specific references to Brussels sprouts throughout Geoff Bond's publications.
Conforming non-starchy, colored plant foods are foods that are low-glycemic, rich in micronutrients and fiber, and harmless with regard to anti-nutrients and antigens. Broadly, they include most salad foods, such as lettuce, onions, cucumber, radish, and mushrooms, and they also include colored vegetables, such as broccoli, green beans, bell peppers (sweet peppers), and Brussels sprouts. These are considered "Green-Green," "Green," and "Green-Amber." Under "Green-Green," we have separated out the vegetables that have the high concentrations of background micronutrients that our ancient ancestors delighted in. You can have unlimited consumption of these foods, and the ideal is up to two pounds (900 g) per day. ~Paleo in a Nutshell p.62
Brussels Sprouts are a low-glycemic, rich in micronutrients and fiber, and harmless with regard to anti-nutrients and antigens. ~Paleo in a Nutshell p.70
modern species of intensively cultivated plants tend to have lower protein content, but there are exceptions: Brussels sprouts contain 24% protein per 100 grams dry-weight. ~Paleo in a Nutshell p.125
The vegetables from above ground cover a huge range of plant parts: stems, such as asparagus from the Mediterranean and kohlrabi from Europe; buds, such as Brussels sprouts from Belgium; leafstalks, such as celery from the Mediterranean and rhubarb from Asia; leaves, such as Europe's cabbage, lettuce, and spinach; immature flowers, such as cauliflower from Europe, broccoli from Turkey, and artichoke from the western Mediterranean; immature fruits, such as eggplant from southern Asia and cucumber from northern India; mature "vegetable-fruits," such as tomato from Peru, avocado from Central America, and bell pepper from the Andes; edible bean pods, such as runner beans from tropical America; and edible fungi (mushrooms) from just about everywhere. Of course, today, these plants are grown all over the world, wherever farmers can produce them economically. ~Deadly Harvest p.56
Can humans get enough protein from plant foods alone? We need less protein than we think— about 75 grams per day for an average 165-pound adult. That equates to about 2 pounds (1 kg) of Brussels sprouts per day. Not impossible! ~Deadly Harvest p.125