I've had gout occasionally and use unsweetened tart cherry juice concentrate (Dynamic Health brand from a health food store), an old wives' remedy for joint inflammation that actually works for me. And there are medical reasons it should work: https://www.healthline.com/health/cherry-juice-for-gout

It has some carbs, but I only take 1 teaspoon at a time which has 2.5 g carbs. Or 2 tsp for 5g. It also comes in capsules, but I haven't tried them.