Mid-cap funds are one of the best options for investors seeking high return potential that comes with lower risk than their small-cap counterparts. Mid-cap funds are not too susceptible to volatility in broader markets, making them ideal bets amid macroeconomic upheavals.

When capital appreciation over the long term takes precedence over dividend payouts, growth funds become natural choices for investors. These funds focus on realizing an appreciable amount of capital growth by investing in stocks of firms whose value is projected to rise over the long term.

However, a relatively higher tolerance to risk and the willingness to park funds for the longer term are necessary when investing in these securities. This is because they may experience relatively more fluctuations than other fund classes.

Below we share with you four top-rated mid-cap growth mutual funds. Each has earned a Zacks Mutual Fund Rank #1 (Strong Buy) and is expected to outperform its peers in the future. Investors can click here to see the complete list of mid-cap growth funds.

Commerce MidCap Growth (CFAGX - MF report) seeks growth of capital. CFAGX invests the lion's share of its assets in securities of mid-cap growth companies, which are those with market capitalization within the range of the Russell Midcap Growth Index. CFAGX generally invests in securities of companies having a history of below-average price volatility. Commerce MidCap Growth has year-to-date, three-year and five-year annualized returns of 10.7%, 11% and 13.8%, respectively.

CFAGX has an expense ratio of 1.03% as compared to the category average of 1.29%.

T. Rowe Price Mid-Cap Growth Advisor (PAMCX - MF report) maintains a diversified portfolio by investing a large chunk of its assets in companies having market capitalization similar to those listed on the S&P MidCap 400 Index or the Russell Midcap Growth Index. PAMCX invests in companies having above-average growth potential. The fund focuses on acquiring common stocks of both domestic and foreign companies. T. Rowe Price Mid-Cap Growth Advisor has year-to-date, three-year and five-year annualized returns of 6%, 12% and 15.9%, respectively.

As of June 2016, PAMCX held 132 issues, with 2.55% of its assets invested in Fiserv Inc.

Voya MidCap Opportunities Port S (ISMOX - MF report) seeks appreciation of capital for the long run. ISMOX invests the majority of its assets in securities of mid-cap companies. The fund normally makes investment in those companies which are believed to have above-average growth prospect. Voya MidCap Opportunities Port S has year-to-date, three-year and five-year annualized returns of 7.3%, 8.1% and 12.9%, respectively.

ISMOX has an expense ratio of 1.06% as compared to the category average of 1.29%.

Dreyfus Mid-Cap Growth F (FRSPX -MF report) invests more than 80% of its assets in securities of companies which falls within the market-cap range of the Russell Midcap Growth Index. FRSPX seeks capital growth. The fund not only invests in domestic companies but also in foreign companies. Dreyfus Mid-Cap Growth F has year-to-date, three-year and five-year annualized returns of 5.1%, 6.5% and 12.4%, respectively.

Robert Zeuthen is the one of the fund managers and has managed FRSPX since 2010.