Nothing provides complete protection, but diversification can help reduce the impact.

The person saying gold and mining stocks may or may not be correct - it's still a risky position. Precious metals could be in a commodity bubble right now (or not). It's had to predict anything with perfect accuracy, which is why diversification matters.

You probably shouldn't be jumping completely in or out of anything because that requires timing, which is also not easy to do. What you can do is change he weights withing your portfolio. For example, reducing your US equity exposure to increase your bond exposure. Or reducing your US growth exposure to increase your US value and Eurozone dividend exposure. It's best to listen to several financial companies reports to weigh what to do.