The Hairspray star admits she is worried Milo, 15, and 11-year-old Owen will get used to their privileged upbringing in the U.S. and will grow up without any idea of the plight of people in impoverished countries.
The boys used their school vacation to travel to the African nation to help a family build its home, and Lake is proud of their accomplishments.
She tells Scholastic Parent & Child magazine, "I want them to be in touch with the real world and to be able to see themselves as just two of the billions of people on this planet.
"There's a lot of charity work that we do as a family; this summer they went to Malawi to build a house for a family that needed a home. Volunteer work is incredible for kids who are growing up rather privileged and need to really get a sense of the world, the big picture.
"Milo and Owen learned first-hand about giving back. Their trip to Africa changed something inside them forever, and they will always carry that experience."