Personal-consumption expenditures, or household spending, edged up a seasonally adjusted 0.1% in August from July, the Commerce Department said Friday. The modest growth marked a sharp pullback from the first seven months of the year, when spending rose an average of 0.5% a month.

American consumers had been a bright spot in the economy. But weaker August spending showed consumers might be succumbing to some of the external headwinds that have shaken businesses and manufacturers for months.

Slowing global growth, fading effects from the 2017 tax cut and rising trade frictions are weighing on the US economy.

Economists lowered their estimates of third-quarter economic growth. Macroeconomic Advisers’ closely watched model for gross domestic product showed growth slowing to 1.7% in the third quarter, down from a previous estimate of 2.2%. Pantheon Macroeconomics, meanwhile, cut its forecast for third-quarter consumer-spending growth to 2.9% from 3.6%.